by Zach Davis, Stuart Enoch, PhD, Noor Sash, PhD u.a.
Everything you ever wanted to know about medicine – in one package!
Lecturio’s “Medicine Flat Rate” includes all current and prospective medical courses. It will provide you with invaluable guidance and comprehensive support for your study and training – not only for medical students, but also for nurses and non-medical practitioners.
You will get access to an impressive variety of lectures held by renowned experts, such as the editor-in-chief of The American Journal of Medicine, Prof. Joseph Alpert.
Our team of highly qualified medical professionals will guide you through the following main topics:
NCLEX-RN Review Course
The courses “Basic and Further Science”, “Internal Medicine” and “Specialties” will be added soon.
Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants are used in the treatment and prevention of thrombotic and embolic diseases including cardioembolic ischemic stroke, acute coronary syndrome, and venous thromboembolism, among other conditions. Patients with atrial fibrillation or thrombophilias may require indefinite or lifelong anticoagulation. Accordingly, the route of administration, drug interactions, pharmacokinetics, and availability of reversal factors should be considered while selecting the anticoagulant therapy.
Acute otitis media is an infection in the middle ear characterized by mucosal inflammation and retention of fluid. The most common pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The condition can present with fever, otalgia, and diminished hearing. Diagnosis is made by history and otoscopic exam showing a bulging tympanic membrane with reduced mobility. Observation or antibiotics are the usual management approaches, but surgery for tympanostomy tubes may be required if there are recurrent infections. Potential complications include hearing loss, tympanic membrane perforation, and mastoiditis.
DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). Conotruncal anomalies present as congenital heart defects. Other manifestations consist of characteristic facial features, frequent infections, and neuropsychiatric disorders.
The phases of the cell cycle include interphase (G1, S, and G2) and mitosis (prophase, metaphase, anaphase, and telophase). The cell’s progression through these phases is punctuated by checkpoints regulated by cyclins, cyclin-dependent kinases, tumor suppressors, and their antagonists.
Giant cell arteritis (GCA), also known as temporal arteritis, is a type of large-vessel vasculitis that predominantly affects the aorta and its major branches, with a predilection for the branches of the carotid (including the temporal artery). Giant cell arteritis is defined by inflammatory leukocytes in the vessel walls leading to reactive damage, ischemia, and necrosis. Giant cell arteritis causes headaches, scalp tenderness, jaw pain, vision problems, and potentially blindness. The diagnosis is made with temporal artery biopsy. Prompt treatment with glucocorticoids can relieve symptoms and prevent vision loss.
Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary edema is easily recognized on a chest X-ray, and an evaluation should be done to identify the underlying cause. Management involves supporting the patient’s respiratory status with oxygen, diuretics, and treatment of the underlying cause.
Galactosemia is a disorder caused by defects in galactose metabolism. Galactosemia is an inherited, autosomal-recessive condition, which results in inadequate galactose processing and high blood levels of monosaccharide. The rare disorder often presents in infants with symptoms of lethargy, nausea, vomiting, diarrhea, and jaundice. Serious neurologic complications such as speech and motor deficits (e.g., ataxia) may occur. Diagnosis is made through blood testing, which detects an absence or low level of the enzymes necessary to process galactose. Treatment is avoidance of lactose and galactose in the diet.
Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. The diagnosis is based on clinical suspicion, and once suspected, immediate empiric treatment is warranted to prevent catastrophic and long-term neurologic sequelae. Encephalitis is managed with supportive measures and antiviral therapy. Focal neurologic defects are common after encephalitis, and hence, physiotherapy is usually required.
Seizures occur when uncontrolled excessive synchronous neuronal activity in the brain causes sudden transient changes in motor function, sensation, behavior, or mental status. Seizures are classified primarily as generalized or focal and may occur once or be recurrent (epilepsy). Prolonged or recurrent seizures lasting > 30 minutes are called status epilepticus. Diagnosis depends on thorough history, physical exam, and EEG findings. Treatment is directed at the underlying trigger, and medications are administered as necessary. Most children that seize recover without any sequelae, but prognosis depends on the initial cause and the presence of underlying neurologic pathology.
Respiratory distress syndrome (RDS), also known as hyaline membrane disease, is caused by the lack of adequate pulmonary surfactant production in an immature lung. The syndrome is most commonly seen in preterm infants. The incidence is inversely related to gestational age, with the highest risk in neonates born at less than 28 weeks. Prenatal assessment of lung maturity and steroid administration can improve outcome if an early delivery cannot be prevented. Diagnosis is clinical. Affected newborns show signs of respiratory distress at birth, or soon thereafter, with nasal flaring, grunting respirations, and retractions. Treatment includes antenatal steroids, exogenous surfactant, and respiratory support. Neonatal RDS is associated with high morbidity and mortality in preterm infants.
Sideroblastic anemias are a heterogeneous group of bone marrow disorders characterized by abnormal iron accumulation in the mitochondria of erythroid precursors. The accumulated iron appears as granules in a ringlike distribution around the nucleus, giving rise to the characteristic morphological feature of a ring sideroblast. Sideroblastic anemias may be due to inherited defects in heme synthesis or can be acquired through alcoholism, lead poisoning, medications, or vitamin deficiencies. The anemia is commonly microcytic with low to normal reticulocyte count. Serum iron levels are typically elevated. A bone marrow examination showing ring sideroblasts establishes the diagnosis. Management involves treating the underlying condition, avoiding causative medication and/or toxins, and phlebotomy in cases of iron overload.
The larynx, also commonly called the voice box, is a cylindrical space located in the neck at the level of the C3–C6 vertebrae. The larynx is continuous superiorly with the oropharynx and inferiorly with the trachea. This structure is made up of 9 cartilages that are connected by membranes, ligaments, and muscles and that house the vocal cords. The major structures forming the framework of the larynx are the thyroid cartilage, cricoid cartilage, and epiglottis. The larynx serves to produce sound (phonation), conducts air to the trachea, and prevents large molecules from reaching the lungs.
The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of 16–20 semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. The posterior wall of the trachea is free of cartilage. In this area, the paries membranaceus forms a plate out of smooth tracheal muscle and connective tissue and forms the border to the dorsally running esophagus.
Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. To perform this function, the lungs need to be able to capture as much O2 as possible, a task that is easily achieved owing to their elastic morphology. Each lung is enclosed within the visceral pleura and completely fills 1 of the non-symmetrical pleural cavities, which are situated on the left and right sides of the mediastinum. The lungs encase the bronchial tree and are divided functionally and anatomically into lobes.
Malignant lesions of the penis arise from the squamous epithelium of the glans, prepuce, or penile shaft. Penile cancer is rare in the United States, but there is a higher prevalence in lower socioeconomic regions. The most common histologic subtype is squamous cell carcinoma. Uncircumcised men and those with HPV infections are at highest risk of penile neoplasms. Diagnosis is a combination of physical exam, history, imaging studies, and tissue biopsy. Proper TNM staging is necessary to determine the correct treatment, which ranges from local topical therapy to multimodal surgery/radiation/chemotherapy.
Acute respiratory distress syndrome is characterized by the sudden onset of hypoxemia and bilateral pulmonary edema without cardiac failure. Sepsis is the most common cause of ARDS. The underlying mechanism and histologic correlate is diffuse alveolar damage (DAD). Diffuse alveolar damage involves damage to the endothelial and alveolar epithelial cells and is associated with inflammation and the development of hyaline membranes lining the inner alveolar walls. The reparative stage follows after weeks, with fibrosis possibly occurring later. Clinically, the following triad of findings favors a diagnosis of ARDS: acute or rapidly progressive dyspnea, hypoxic respiratory failure (partial pressure of O2/fraction of inspired O2 ratio < 300 mm Hg), and bilateral alveolar opacities on chest imaging. Management involves determination and treatment of the cause while providing adequate oxygen, reducing further lung damage, and avoiding fluid overload. Most patients require mechanical ventilation. Acute respiratory distress syndrome is associated with high mortality or long-term complications potentially developing even after treatment.
The wrist connects the forearm to the hand. It consists of 8 carpal bones, multiple joints, and various supporting ligaments, as well as the distal bones of the forearm and the proximal portion of the 5 metacarpal bones of the hand. The wrist is crucial for the functioning of the upper limb, and it provides stability while positioning the hand for intricate motions.
Atelectasis is the partial or complete collapse of a part of the lung. Atelectasis is almost always a secondary phenomenon from conditions causing bronchial obstruction, external compression, surfactant deficiency, or scarring. Hypoxemia can occur as a result of blood flowing through unventilated lung segments. Patients are often asymptomatic. However, dyspnea, cough, chest pain, and fever can also occur. The diagnosis is made with imaging. Management includes treatment of the underlying etiology, lung expansion exercises, chest physiotherapy, bronchodilators, and bronchoscopy in select cases.
Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. A thorough history and physical examination guide the work-up to uncover the underlying cause. The causes of FTT are divided into nonorganic and organic. A multidisciplinary approach is taken in the management of nonorganic causes of FTT; organic causes require management of the underlying cause. Recognition and treatment of FTT are important to avoid developmental delay.
Malingering is not a medical disorder, but a behavior of an individual. Malingering is characterized by the intentional falsification of symptoms for an external benefit. Patients may either invent new ailments or exaggerate current symptoms. Common examples of secondary gain include financial compensation, avoidance of work, obtainment of prescription medications, and avoidance of criminal charges. After ruling out organic medical diseases, providers must confront the individual in a nonjudgmental fashion.
Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Depending on the location of the infection, patients can present with dysuria, urinary urgency, increased urinary frequency, suprapubic pain, and fever. Urinalysis and urine culture along with the clinical presentation help in the diagnosis of UTIs. Management options include oral or IV antibiotics such as trimethoprim-sulfamethoxazole, nitrofurantoin, and ceftriaxone. In certain instances, further workup may be needed to determine the underlying conditions that predispose an individual to UTIs.
Hemoptysis is defined as the expectoration of blood originating in the lower respiratory tract. Hemoptysis is a consequence of another disease process and can be classified as either life threatening or non-life threatening. Only 5%–15% of patients with hemoptysis have life-threatening bleeding. However, hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. The most common causes of hemoptysis include bronchiectasis, lung cancer, tuberculosis, and aspergillosis. Diagnosis involves chest imaging and bronchoscopy. In cases of life-threatening bleeding, treatment is initially directed at stabilizing the patient and, if bleeding is ongoing, hemostasis can often be achieved with minimally invasive techniques (e.g., arterial embolization).
Megaloblastic anemia is a subset of macrocytic anemias that arises because of impaired nucleic acid synthesis in erythroid precursors. This impairment leads to ineffective RBC production and intramedullary hemolysis that is characterized by large cells with arrested nuclear maturation. The most common causes are vitamin B12 and folic acid deficiencies, which can be due to low dietary intake, underlying malabsorptive conditions, and medications. Clinical presentation includes anemia and GI symptoms, with neurologic manifestations more commonly seen in B12 deficiency. Laboratory tests show macrocytic anemia (elevated mean corpuscular volume) and low B12 and folate levels. Confirmatory tests can be performed if levels are borderline. Treatment focuses on identifying the cause of the deficiency and replacing the deficient vitamin either orally or parenterally.
Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). There are hundreds of AAs found in nature, but only 20 are the building blocks of proteins in humans (proteinogenic). Nine of these 20 are “essential,” as they cannot be synthesized. Amino acids differ from one another only in the chemical nature of the R group. They are most commonly classified according to their interaction with water as hydrophobic, hyd
Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000–450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Clinical manifestations of thrombocytopenia include easy bruising or bleeding, petechiae, purpura, and when severe, spontaneous mucosal and/or internal bleeding. Diagnosis is made with a CBC and blood smear; additional testing may be required to determine the underlying etiology if it is not evident from the clinical scenario. Management involves treating the underlying etiology and platelet transfusions.
Lung development involves 5 stages: embryonic, pseudoglandular, canalicular, saccular, and alveolar. The inner respiratory epithelium arises from the endoderm, and the cartilage, bronchial muscles, connective tissue, and vasculature all arise from the mesoderm. Starting in the embryonic stage at 4 weeks of development, the lung bud branches off the ventral side of the foregut, forming the esophagus posteriorly and the trachea anteriorly. In the pseudomembranous stage, the trachea undergoes multiple generations of branching, and in the canalicular stage, primitive alveolar structures and capillaries develop. Next, in the saccular stage, gas exchange becomes possible as the capillaries more closely associate with maturing alveoli, and type II pneumocytes have started secreting surfactant. In the alveolar stage, the alveoli continue to grow in number and size and continue to mature until a child is 8 years old.
Hemostasis refers to the innate, stepwise body processes that occur following vessel injury, resulting in clot formation and cessation of bleeding. Hemostasis occurs in 2 phases, namely, primary and secondary. Primary hemostasis involves platelet adhesion, activation, and aggregation to the damaged vascular endothelium, forming a plug that stops the bleeding temporarily. Secondary hemostasis involves the activation of the coagulation cascade resulting in the formation of a more stable plug. Finally, as the vasculature is repaired, the clot is broken down in the fibrinolytic phase.
Botulism is a rare, neuroparalytic syndrome caused by Clostridium botulinum (C. botulinum). A fatal neurotoxin (botulinum toxin) is released causing varying degrees of muscle paralysis and distinct clinical syndromes. The most common types of botulism are foodborne and infant. Botulism presents with blurred vision, respiratory failure, and symmetric, descending flaccid paralysis. Characterization includes intact sensorium, normal heart rate and blood pressure, absence of fever, and absence of sensory deficits. Diagnosis is made on clinical grounds and can be confirmed by the isolation of bacteria or toxins from stool, wound specimens, or food sources. The approach to managing a case of botulism should include prompt management of respiratory failure, administration of antitoxin, and supportive care for paralysis.
Esophageal rupture or perforation is a transmural defect that occurs in the esophagus, exposing the mediastinum to GI content. The most common cause of esophageal perforation is iatrogenic trauma by instrumentation or surgical procedures. Perforation can also be due to foreign body ingestion or non-iatrogenic trauma produced by severe vomiting. Esophageal perforation presents with substernal chest pain that can have a sudden or insidious onset. Diagnosis can be achieved through a CT scan of the chest and neck, chest X-ray, or esophagogram. Management commonly includes surgical repair of the transmural esophageal defect. However, conservative therapy may also be considered for a hemodynamically stable patient with a minor defect. The main complication of esophageal perforation is acute mediastinitis. The mortality rate can range from 10%–50%.
Malaria is an infectious parasitic disease affecting humans and other animals. Most commonly transmitted via the bite of an infected female Anopheles mosquito, malaria is caused by single-celled microorganisms of the Plasmodium genus. Patients present with fever, chills, myalgia, headache, and diaphoresis after a history of exposure in an area endemic to malaria, which is often cyclical. Prophylaxis is of utmost importance. Treatment with oral medications is available, but malaria can be severe and fatal without a timely diagnosis, especially in young children.
Otitis externa (also known as external otitis or swimmer’s ear) is an infection of the external auditory canal that is most often caused by acute bacterial infection and is frequently associated with hot, humid weather and water exposure. Patients commonly present with ear pain, pruritus, discharge, and hearing loss. The diagnosis is made clinically. Most types of otitis externa are treated with topical antibiotic therapy. Complications include periauricular cellulitis and malignant otitis externa.
Computed tomography (CT) is one of the most commonly used imaging methods because it is widely available, fast, and reliable. CT scans deploy X-rays to obtain cross-sectional images of the body. A CT scanner consists of a tube that rotates around the patient and emits an X-ray beam and a detector that uses specialized software to receive and convert the beam to an image. The ability to create multiple views (axial, sagittal, coronal) and use contrast (intravenous, oral, rectal) allows for enhanced diagnostic yield. Patients are exposed to radiation, and special consideration should be given to patients with a history of iodine allergy, renal disease, or thyroid disease or patients who are pregnant.
Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. DIC is always triggered by another (often serious) condition, including severe sepsis, trauma, malignancy, or obstetric complications. Acute DIC often presents dramatically, with rapid onset of spontaneous bleeding from multiple locations throughout the body simultaneously. A chronic form of DIC also exists, typically in patients with late-stage malignancies. Management involves stabilizing the patient, replacing consumed platelets and coagulation factors, and treating the triggering condition.
Myasthenia gravis (MG) is an autoimmune neuromuscular disorder characterized by weakness and fatigability of skeletal muscles caused by dysfunction/destruction of acetylcholine receptors at the neuromuscular junction. Myasthenia gravis presents with fatigue, ptosis, diplopia, dysphagia, respiratory difficulties, and progressive weakness in the limbs, leading to difficulty in movement. Diagnosis is established based on clinical presentation, detection of antibodies, and electrophysiologic studies. Management is aimed at increasing the activity of acetylcholine at the neuromuscular junction and suppression of antibodies. This disease can be associated with thymomas and thymic hyperplasia, and thymectomy is sometimes indicated. Myasthenia gravis can progress to a life-threatening cholinergic crisis with respiratory failure, but this is preventable with appropriate management. Prognosis is generally good with treatment, and some patients can achieve a long-term remission.
Hyperkalemia is defined as a serum potassium (K+) concentration > 5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia is usually asymptomatic if minor in severity; however, acute elevations or severe hyperkalemia can lead to potentially fatal cardiac arrhythmias. Management is guided by severity and includes measures to stabilize the myocardial membrane potential, transiently shifting K+ intracellularly, removing K+ from the body, and treating the underlying predisposing conditions.
Vomiting, or emesis, is the forceful oral expulsion of gastric contents. Vomiting is a common presenting symptom in pediatrics. The frequency and characteristics of vomiting may point toward a specific pathology, just as its presence can be another symptom of a greater clinical situation. The majority of vomiting symptoms are benign and self-limited. A good history and physical examination can bring into focus the underlying cause and workup. Management is with antiemetics and treating the underlying cause, if needed. The most common complications are dehydration and malnutrition.
Thoracic outlet syndrome (TOS) is a broad term used for a spectrum of syndromes related to the general region of the thoracic outlet, which involves the compression or irritation of elements of the brachial plexus, subclavian artery, or subclavian vein. The most common etiology involves structural abnormalities. Thoracic outlet syndrome can present as the neurogenic, arterial, or venous type. The neurogenic type is the most common among the 3 variants and mainly involves the inferior trunk of the brachial plexus (C8–T1). Signs and symptoms vary based on the structure that is involved. The diagnosis of TOS is clinical and supported by radiography and a number of provocation maneuvers. Untreated TOS can lead to various complications such as a frozen shoulder. Management of TOS is using pharmacological and surgical methods.
Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Patients typically present with shortness of breath initially during exercise and then at rest. Diagnosis may involve an echocardiogram, ECG, chest X-ray, pulmonary function tests, a ventilation-perfusion scan, laboratory testing for conditions associated with PAH, and/or cardiac catheterization. Management is often complex and aimed at treating the underlying etiology. Several classes of vasodilatory agents may be used for patients with primary PAH, including calcium channel blockers and vasoactive prostaglandins.
Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. A number of etiologies exist, including diseases of the lungs, cardiovascular, and nervous system. Patients with respiratory failure may present with dyspnea, tachypnea, and altered mentation. The diagnosis is made with arterial blood gas and supplemented with laboratory and imaging studies to elicit an etiology. Management involves treating the underlying cause, supplemental oxygen administration, and mechanical ventilation for severe cases.
A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. Additionally, the cell membrane allows the cell to communicate with other cells and also helps in tissue formation. Membranes are formed when glycerophospholipids and sphingolipids interact and expose their polar heads to the aqueous extracellular environment while sequestering their nonpolar tails toward the middle of the membrane. Proteins that are anchored in the membrane are responsible for cell signaling and interactions, transmembrane transport of substances, and for providing cellular structure.
Nephrolithiasis is the formation of a stone, or calculus, anywhere along the urinary tract caused by precipitations of solutes in the urine. The most common type of kidney stone is the calcium oxalate stone, but other types include calcium phosphate, struvite (ammonium magnesium phosphate), uric acid, and cystine stones. Nephrolithiasis presents with colicky flank pain, which radiates to the groin, and hematuria due to damage to the ureters. Diagnosis is made by noncontrast CT of the abdomen and pelvis or by renal ultrasound, and urinalysis is performed to exclude concomitant urinary tract infection (UTI). Management depends on the size of the stone. Small stones likely to pass on their own are managed conservatively with hydration and analgesics. Large stones unlikely to pass spontaneously are managed with extracorporeal shock wave lithotripsy (ESWL), ureterorenoscopy, or percutaneous nephrolithotomy. Nephrolithiasis can be complicated by hydronephrosis or acute pyelonephritis. Adequate hydration is the best prophylactic intervention to prevent kidney stones.
Bronchiectasis is a chronic disease of the airways that results from permanent bronchial distortion. This results from a continuous cycle of inflammation, bronchial damage and dilation, impaired clearance of secretions, and recurrent infections. Most cases are idiopathic, though infections, bronchial obstruction, congenital disorders, and systemic conditions can contribute. Patients present with slowly progressive symptoms of cough and sputum production. The diagnosis is made from characteristic radiographic findings, such as bronchial wall thickening and luminal dilatation. Management focuses on improving clearance of mucus, relieving airway obstruction, treating infection, and managing the underlying etiology. Management can include chest physiotherapy, bronchodilators, and antibiotics.
Renal Na+ and water regulation work in tandem to control how fluid is distributed throughout the compartments of the body. Sodium is the body’s dominant extracellular solute, and is responsible for the osmotic force that keeps differing amounts of water in each compartment. Changes in Na+ balance are sensed by the body through changes in blood volume. Changes in water balance are sensed by the body through changes in plasma osmolality. Both ultimately send feedback signals to the kidneys to ensure that homeostasis is maintained. Abnormalities in these processes can result in problems in volume status (e.g., hypertension, pulmonary edema, pitting edema) and dysnatremias (hyponatremia and hypernatremia).
Pericardial effusion is the accumulation of excess fluid in the pericardial space around the heart. The pericardium does not easily expand; thus, rapid fluid accumulation leads to increased pressure around the heart. The increase in pressure restricts cardiac filling, resulting in decreased cardiac output and cardiac tamponade. Signs and symptoms usually occur in the setting of cardiac tamponade and include dyspnea, hypotension, muffled heart sounds, jugular venous distension, and pulsus paradoxus. The diagnosis of pericardial effusion is confirmed with echocardiography. Small effusions in stable patients are treated medically. Larger effusions and cardiac tamponade may require pericardiocentesis or pericardiotomy.
Acute abdomen, which is in many cases a surgical emergency, is the sudden onset of abdominal pain that may be caused by inflammation, infection, perforation, ischemia, or obstruction. The location of the pain, its characteristics, and associated symptoms (e.g., jaundice) are important tools that help narrow the differential diagnosis. Patients will typically have severe tenderness with associated rigidity and rebound tenderness. Laboratory evaluation will demonstrate leukocytosis, acidosis, and in some cases, abnormal hepatic function tests. Imaging helps narrow the differential diagnosis; first-line imaging is always an upright chest X-ray to evaluate for pneumoperitoneum. The treatment and prognosis of acute abdomen strongly depend on the underlying cause, but the vast majority of these cases constitute a surgical emergency with associated morbidity and mortality.
Coronary heart disease (CHD), or ischemic heart disease, describes a situation in which an inadequate supply of blood to the myocardium exists due to a stenosis of the coronary arteries, typically from atherosclerosis. The myocardium becomes ischemic when oxygen supply does not meet oxygen demand. Diagnosis is based on history and ECG findings; cardiac stress tests and catheterizations may also be needed. Treatment is primarily based on reducing the heart's oxygen demand and increasing the delivery of oxygen.
Wilms tumor is a malignancy caused by proliferation of metanephric blastema in the kidneys and is the most common renal malignancy in children. Wilms tumor usually arises sporadically, but it can also occur as a result of a specific congenital anomaly like WAGR (Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation) syndrome, Denys–Drash syndrome, or Beckwith–Wiedemann syndrome. Wilms tumor commonly presents as a firm, nontender, smooth mass that does not cross the midline. Wilms tumor can also rarely present with abdominal pain, hematuria, and/or hypertension. The malignancy is diagnosed with abdominal ultrasonography and histopathologic studies (from biopsy or resection). Wilms tumor is treated with multimodal therapy (surgery, chemotherapy, radiation). Influenced by patient age, molecular markers, and pathologic findings, prognosis is favorable overall, with 5-year survival rates approaching 90%.
Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. The course of myocarditis may vary based on the etiology and timeline of symptom progression. The diagnosis is supported by clinical findings, laboratory evaluation, and cardiac imaging. A definitive diagnosis by endomyocardial biopsy is rarely required. Management is supportive and aimed at addressing complications.
Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. The replication cycle differs between viruses that infect bacteria (bacteriophages) and viruses that infect eukaryotic cells. Bacteriophages have either a lytic or lysogenic replication cycle, while eukaryotic viruses have a defined 6-step replication process.
Adrenal insufficiency (AI) is the inadequate production of adrenocortical hormones: glucocorticoids, mineralocorticoids, and adrenal androgens. Primary AI, also called Addison’s disease, is caused by adrenal gland disorder (autoimmune disease, infections, and malignancy, among others). Adrenal insufficiency can also occur because of decreased production of adrenocorticotropic hormone (ACTH) from disease in the pituitary gland (secondary) or hypothalamic disorders and prolonged glucocorticoid therapy (tertiary). Diagnosis is by demonstrating hypocortisolism (via cortisol and ACTH levels and ACTH-stimulation test) and determining the etiology (adrenal autoantibodies, imaging). Glucocorticoid replacement is needed in all forms of AI. Additionally, in primary AI, mineralocorticoid is given to prevent volume depletion, salt loss, and hyperkalemia. Adrenal crisis is a medical emergency; management requires prompt IV hydration and administration of IV glucocorticoids without waiting for initial hormone results.
Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. It manifests itself as vessel stenosis and a source of thromboembolic disease. Its clinical manifestations depend on the specific vessels affected and include most notably coronary artery disease, carotid disease, and peripheral vascular disease. It is the most common primary disease of the arterial vascular system and is responsible for coronary heart disease, the leading cause of death worldwide.
Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). The list of causes is extensive, ranging from familial disorders to underlying diseases and infections. Patients often present with chest pain, dyspnea, palpitations, and/or syncope. Some patients may be completely asymptomatic, while others may present with sudden cardiac death as the first sign of an underlying condition. Diagnosis is made through the use of ECG and cardiac imaging such as echocardiography and cardiac MRI. Management involves medications typically used to treat heart failure, as well as implantable devices. In severe cases, heart transplantation may be necessary.
Hemolytic disease of the fetus and newborn (HDFN), also known as erythroblastosis fetalis, is caused by maternal IgG antibody destruction of the fetal RBCs. Rhesus (Rh) blood group incompatibility (frequently triggered by D antigen) and ABO incompatibility are common causes. In Rh incompatibility, an RhD-negative mother carries an RhD-positive baby; thus, antibodies form against antigens when fetal RBCs cross into the maternal circulation. In ABO incompatibility, commonly, a mother with blood type O has existing antibodies to A and B antigens. The affected baby can suffer from hemolytic anemia leading to severe neonatal jaundice, hydrops fetalis, cardiac complications, and fetal demise. If the pregnancy is affected by Rh incompatibility, antenatal surveillance is done to determine the need for intrauterine transfusion and early delivery. Postnatal treatment includes close monitoring, phototherapy for jaundice, and exchange transfusion in severe cases. For RhD-negative mothers, maternal sensitization can be prevented by using anti-D immunoglobulin (RhoGAM). Prognosis is excellent with prenatal care, blood type screening, and availability of RhD immune globulin.
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are both rare autosomal neurodevelopmental genetic disorders mapped to a specific region of chromosome 15 attributed to genomic imprinting. This means that the phenotype depends on the gender of the parent donating the genes. A paternally derived chromosome 15 with this deletion results in 15q11-13 paternal deletion syndrome, or PWS, whereas a maternally derived chromosome 15 with a similar deletion is associated with AS. Diagnosis is established with genetic testing. Management is mostly supportive and is focused on early intervention for developmental, neurologic, and physical abnormalities.
Thyroid cancer is a malignancy arising from the thyroid gland cells: thyroid follicular cells (papillary, follicular, and anaplastic carcinomas) and calcitonin-producing C cells (medullary carcinomas). Rare cancers are derived from the lymphocytes (lymphoma) and/or stromal and vascular elements (sarcoma). Driver mutations involving the receptor tyrosine kinase pathway (such as RET and BRAF) and a family history of cancer or related syndromes increase the risk. Exposure to ionizing radiation and iodine deficiency are also considered risk factors. The major types can present as thyroid nodules or enlarged cervical lymph nodes. The diagnostic approach includes thyroid-stimulating hormone, ultrasonography, and biopsy. Treatment options are surgical removal of the thyroid gland, with the addition of radioactive iodine therapy and systemic therapy, depending on the type and extent of the thyroid malignancy.
Thyrotoxicosis refers to the classic physiologic manifestations of excess thyroid hormones and is not synonymous with hyperthyroidism, which is caused by sustained overproduction and release of T3 and/or T4. Graves’ disease is the most common cause of primary hyperthyroidism, followed by toxic multinodular goiter and toxic adenoma. Subacute thyroiditis is an example of thyrotoxicosis without hyperthyroidism, and a pituitary adenoma, which secretes thyroid-stimulating hormone (TSH) is an example of secondary hyperthyroidism. Clinical features of thyrotoxicosis are mostly due to an increase in the metabolic rate and overactivity of the sympathetic nervous system (i.e., an increase in the β-adrenergic “tone”). Thyrotoxicosis is diagnosed by measuring the levels of TSH produced by the anterior pituitary gland and unbound T4 and T3. Depending on the etiology and clinical presentation, it may be treated pharmacologically, surgically, or with radioiodine.
Multiple endocrine neoplasia syndromes are autosomal dominant inherited conditions characterized by 2 or more hormone-producing tumors involving the endocrine organs. There are different types of MEN, namely MEN1–4. The MEN1 syndrome is associated with MEN1 gene mutation and has a predilection for primary hyperparathyroidism, pituitary adenomas, and pancreatic tumors (the 3 P’s). Due to the RET proto-oncogene mutation, MEN2 syndrome can be further categorized as MEN2A and MEN2B. Medullary thyroid carcinoma and pheochromocytoma are common features. The MEN2A variant is associated with primary hyperparathyroidism, whereas MEN2B (also considered MEN3) is associated with neuromas and Marfanoid habitus. The newer and rare entity, MEN4, has features of MEN1 but results from CDKN1B mutations. The diagnosis is clinical, and tumors are detected based on imaging and correlating hormone levels. Genetic testing plays a crucial role in MEN2 syndromes in determining further management. Treatment is dependent on the tumors that are present and genetic mutation.
Hypoparathyroidism is defined as reduced parathyroid hormone (PTH) levels due to poor function of the parathyroid glands. The cause of hypoparathyroidism is most commonly iatrogenic following neck surgery, but it can also be associated with genetic or autoimmune disorders as well as infiltrative diseases causing destruction of the normal parathyroid tissue. Deficiency of PTH results in hypocalcemia, which leads to increased neuromuscular excitability and osteosclerosis, as well as cardiac and neuropsychiatric manifestations. Treatment is based on calcium and vitamin D supplementation.
Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Pruritus is a cardinal symptom. Diagnosis is established clinically. The mainstays of management are avoidance of triggers, emollients, and topical corticosteroids.
The pulmonary examination is a portion of the physical examination involving the assessment of the lungs and airways by a healthcare worker to evaluate for signs of disease or illness. The examination includes inspection, auscultation, percussion, and palpation. A careful pulmonary exam provides important clues that, along with the history, can guide the physician to a presumptive diagnosis.
A goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Hashimoto’s thyroiditis is associated with a benign hypothyroid goiter, while Graves’ disease produces a toxic or hyperthyroid goiter. Nontoxic goiter is euthyroid and is usually due to iodine deficiency (the most common cause of goiter). Diagnostic tests include thyroid function tests and measurement of thyroid antibodies. Ultrasound, CT, and/or MRI help if lab results are ambiguous and if worrisome features such as obstructive symptoms are present. Radioactive iodine uptake distinguishes hyperthyroid causes. Treatment depends on the underlying condition; options include observation, medication, surgery, and radioiodine ablation.
Crohn's disease is a chronic, recurrent condition that causes patchy transmural inflammation that can involve any part of the gastrointestinal tract. It is a type of inflammatory bowel disease (IBD) along with ulcerative colitis (UC). The terminal ileum and proximal colon are usually affected. Crohn's disease typically presents with intermittent, non-bloody diarrhea and crampy abdominal pain. Extraintestinal manifestations may include calcium oxalate renal stones, gallstones, erythema nodosum, and arthritis. Diagnosis is established via endoscopy with biopsy that shows transmural inflammation, characteristic “cobblestone” mucosa, and noncaseating granulomas. Management is with corticosteroids, azathioprine, antibiotics, and anti-TNF agents (infliximab and adalimumab). Complications include malabsorption, malnutrition, intestinal obstruction or fistula, and an increased risk of colon cancer.
Ulcerative colitis (UC) is an idiopathic inflammatory condition that involves the mucosal surface of the colon. It is a type of inflammatory bowel disease (IBD), along with Crohn's disease (CD). The rectum is always involved, and inflammation may extend proximally through the colon. Ulcerative colitis causes diffuse friability, erosions with bleeding, and loss of haustra, which are visible on endoscopy. Patients typically present with bloody diarrhea, colicky abdominal pain, tenesmus, and fecal urgency. Diagnosis is established via endoscopy with biopsy and by ruling out other causes of bloody diarrhea. Management is primarily through topical mesalamine, 6-mercaptopurine, or colectomy for severe cases. Complications include fulminant colitis, toxic megacolon, intestinal perforation, and increased risk of colorectal cancer.
Ichthyosis vulgaris is the most common type of keratinization disorders. The condition occurs due to an autosomal dominant mutation in the filaggrin gene, which results in skin-barrier dysfunction. Patients present in early childhood with rough, dry, and scaly skin that worsens during cold, dry months. The diagnosis is usually clinical, but often aided with a skin biopsy showing hyperkeratosis and a diminished stratum granulosum. Emollients, moisturizers, keratolytics, and retinoids are the mainstays of management.
Urticaria is raised, well-circumscribed areas (wheals) of edema (swelling) and erythema (redness) involving the dermis and epidermis with associated pruritus (itch). Urticaria is not a single disease but rather is a reaction pattern representing cutaneous mast cell degranulation resulting in the release of histamine and other vasoactive substances from mast cells and basophils in the dermis resulting in extravasation of plasma into the dermis. Urticaria can be caused by myriad inciting events, such as allergic reactions, infections, exposure, and many others. The diagnosis is made clinically. H1-antagonists are used as 1st-line treatment.
Hypertrophic cardiomyopathy (HCM) is the most commonly inherited cardiomyopathy, which is characterized by an asymmetric increase in thickness (hypertrophy) of the left ventricular wall, diastolic dysfunction, and often left ventricular outflow tract obstruction. Hypertrophic cardiomyopathy is caused by various gene mutations affecting the contractile components of the heart, known as sarcomeres. Inheritance of HCM is typically autosomal dominant, although sporadic mutations also occur. Patients may be asymptomatic, present with dyspnea and chest pain or suffer sudden cardiac death without prior symptoms. Diagnosis is made based on ECG, echocardiography, stress test, and cardiac MRI. Symptomatic HCM is typically treated with beta-blockers as the 1st-line therapy. Additional management depends on the presence of left ventricular outflow tract obstruction.
Personality disorders are ego-syntonic behaviors that begin in childhood or adolescence and are classified into 3 clusters: A, B, and C. They can considerably interfere with a patient’s adherence to medical treatment for a variety of reasons. It is important to rule out organic causes of a mental disorder (e.g., endocrine hormone imbalances, medication adverse effects, alcohol and/or substance use, other mental health co-morbidities) before ascribing a personality disorder to a patient. Cluster A includes paranoid, schizoid, and schizotypal personality disorders, which can be behaviorally described as being distrustful and/or detached from society.
Cardiac arrest is the sudden, complete cessation of cardiac output with hemodynamic collapse. Patients present as pulseless, unresponsive, and apneic. Rhythms associated with cardiac arrest are ventricular fibrillation/tachycardia, asystole, or pulseless electrical activity. The treatment of cardiac arrest begins with basic life support (BLS) when out-of-hospital and advanced cardiac life support (ACLS) when in-hospital. Basic life support comprises checking the patient’s mental status, activating the emergency response system, and cardiopulmonary resuscitation (CPR). An automated external defibrillator (AED) should be used once available. High-quality CPR (with early defibrillation in shockable rhythms) is crucial to survival in cardiac arrest. Advanced cardiac life support includes CPR, securing the airway, administering medications (such as epinephrine), and identifying and treatment of the cause of cardiac arrest. Post-cardiac arrest care follows return of spontaneous circulation (ROSC).
Heatstroke is an illness characterized as a core body temperature exceeding 40°C (104°F) with accompanying neurological symptoms including ataxia, seizures, and/or delirium. Heatstroke is usually due to the body’s inability to regulate its temperature when challenged with an elevated heat load. The illness can be classified as exertional or non-exertional. Management involves emergent stabilization, cooling, and supportive care. Early recognition and intervention are important to prevent complications or organ failure.
Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto's disease (autoimmune thyroiditis) is the leading cause in non–iodine-deficient regions. Primary hypothyroidism occurs with thyroid gland disorders, while the central type arises from pituitary and hypothalamic conditions. Thyroid hormones are integral in metabolic processes and in the development of the brain and other organs. Congenital hypothyroidism can result in significant mental disability due to the loss of thyroid hormones. The features of acquired hypothyroidism also reflect the effects of slowed organ function, such as fatigue, bradycardia, cold intolerance, and exertional dyspnea. Diagnosis is by thyroid function testing. Elevated thyroid stimulating hormone and low free thyroxine (T4) levels are noted. Treatment is with synthetic T4.
Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Important clinical exam findings include a new or changed heart murmur and common extra-cardiac signs, such as Osler nodes, Janeway lesions, splinter hemorrhages, and Roth spots. The diagnosis is based on clinical findings, blood cultures, and echocardiography showing valvular vegetations. Management includes intravenous antibiotics for infectious cases, addressing the underlying etiology for noninfectious cases, and surgical repair when necessary.
Health care maintenance is the examination of asymptomatic individuals and screening for any occult disease. The process provides an opportunity for disease prevention and early diagnosis and the possibility of preventing progression and complications. During a health care maintenance examination, the primary physician conducts a thorough personal, social, and family history with a comprehensive systematic review to uncover any relevant risk factors. A physical examination is performed, and relevant screening exams are recommended. Screening tests cover malignancies (breast, prostate, colon, lung) and other conditions, including diabetes, cardiovascular diseases, and infections. Immunizations are administered if indicated. Different interventions are discussed to help reduce health risk factors, and health goals are set to determine future follow-up and monitoring.
The shoulder complex comprises the glenohumeral joint, sternoclavicular joint, acromioclavicular joint, and the scapulothoracic articulation, and connects the upper limb to the trunk. This group of joints consists of the clavicle, scapula, and humerus bones, multiple muscles and supporting ligaments, cartilage, and bursae. The muscles ensure the mobility and stability of the shoulder and upper limb and are divided into 3 groups: anterior axioappendicular, posterior axioappendicular, and scapulohumeral muscles.
Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Several conditions are associated with obesity, including diabetes, hypertension, and heart disease, all of which contribute to significant healthcare costs. Diagnosis is most commonly based on BMI measurement, wherein obesity is defined as BMI > 30. Management includes lifestyle changes, medications, or, in severe cases, bariatric surgery.
Immune thrombocytopenic purpura (ITP), formerly known as idiopathic thrombocytopenic purpura, is a condition that develops secondary to immune-mediated destruction of platelets, resulting in thrombocytopenia (platelet count < 100,000/mm³). Immune thrombocytopenic purpura can be either primary or secondary due to drugs or underlying disease. The diagnosis is usually one of exclusion. Many patients with ITP are asymptomatic. When present, symptoms are primarily related to bleeding (e.g., bruising, petechiae, epistaxis), but fatigue is also common. The severity of thrombocytopenia in patients with ITP is variable. When platelet counts drop to < 20,000/mm³, the risk of serious bleeding increases. Treatment may include platelet transfusion, steroids, IV immune globulins, and/or splenectomy. Some cases remit spontaneously; others generally have a good prognosis with appropriate therapy.
Necrotizing enterocolitis (NEC) is an intestinal inflammatory process that can lead to mucosal injury and necrosis. The condition is multifactorial, with underlying risk factors that include prematurity and formula feeding. The clinical presentation varies in severity from feeding intolerance, acute findings on abdominal exam, and systemic symptoms. The diagnosis is based on a clinical suspicion, abnormal abdominal radiographs, and supporting abnormal laboratory results. Management consists of supportive medical care for milder stages and bowel rest and surgical intervention for more advanced stages. Necrotizing enterocolitis and its complications carry a high risk of morbidity and mortality.
Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Sexual contact is a common route of spread for HPV. While seen in all populations and ages, condylomata acuminata is most often seen in adolescence. HPV types 6 and 11 are responsible for 90% of warts and are considered low risk for malignancy; however, other types of HPV should be considered. Lesions rarely self-resolve; however, they can be removed via cryotherapy or topical antimitotic agents. While there is currently no treatment for HPV infection, it can be prevented through vaccination.
Primary amenorrhea is defined as the absence of menstruation in a girl by age 13 years in the absence of secondary sex characteristics or by the age of 15 years with the presence of secondary sex characteristics. Etiologies can originate in the hypothalamic–pituitary–ovarian (HPO) axis or from anatomic abnormalities in the uterus or vagina. Sometimes other endocrinopathies interfere with the sex hormones enough to suppress menstruation. Important factors to assess when working through the differential diagnosis are whether the patient has breast development (indicating exposure to estrogen from functional ovaries), the presence or absence of a uterus (indicating a potential genetic anomaly), and whether follicle-stimulating hormone (FSH) levels are high, low, or normal (providing insight into the HPO axis). Management includes correcting the underlying hormonal or anatomic issue, providing hormone replacement therapy (HRT), addressing fertility implications, and psychotherapy.
Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, refers to the rupture of the amniotic sac before the onset of labor. Prelabor rupture of membranes may occur in term or preterm pregnancies. The presentation includes a painless discharge of clear or pale-yellow fluid from the vagina in the form of a large gush or as small, intermittent trickles. Management depends on gestational age. Beyond 34 weeks, the recommendation is to induce labor and, if indicated, use antibiotics for group B streptococcus (GBS) prophylaxis. Prior to 34 weeks, management involves prolonging the pregnancy as long as possible while avoiding intra-amniotic infection (IAI), also known as chorioamnionitis, and minimizing risk to the fetus. The primary complications associated with PROM are related to infections and preterm birth.
Nephrotic syndrome is a renal disorder caused by conditions that increase the permeability of the glomerular filtration barriers. Nephrotic syndrome affects all age groups but has a higher pediatric prevalence. This disorder can be due to both primary (renal) and secondary (systemic) causes. Minimal change disease (MCD), is the most common presentation in children. Hallmark features include proteinuria of > 40 mg/m²/day, hypoalbuminemia, hypercholesterolemia, and edema. Diagnosis is based on history, physical exam, laboratory tests confirming nephrotic-range proteinuria and workup for systemic disease. Genetic testing is recommended in some cases. Steroids are the initial treatment in a classic presentation of the typically steroid-responsive MCD. In other cases, renal biopsy is indicated. Management and prognosis vary depending on the underlying cause and response to steroids.
Orbital and preseptal cellulitis are infections differentiated by the anatomic sites affected in the orbit. Infection anterior to the orbital septum is preseptal cellulitis; infection posterior to the septum is orbital cellulitis. Inoculation with the pathogen can occur through trauma or surgery. Cellulitis also occurs via extension from a nearby structure (such as from sinus infection or sinusitis). Patients will have eyelid erythema, pain, and swelling. Distinguishing characteristics of orbital cellulitis include ophthalmoplegia, proptosis, painful eye movement, and possible vision impairment. Complications are rare with preseptal cellulitis, and treatment can be initiated with oral antibiotics. Orbital cellulitis, however, requires intravenous broad-spectrum antibiotics and in severe cases, surgical drainage.
Pityriasis rosea is an acute, self-limited skin disease. The etiology is not known, and it commonly occurs in young adults. Patients initially present with a single, ovoid “herald patch.” This is followed by diffuse, pruritic, scaly, oval lesions over the trunk (often in a “Christmas tree” distribution on the back) and extremities. The diagnosis is clinical. Pityriasis rosea is a self-limiting condition; therefore, usually no treatment is required. However, topical steroids and antihistamines may be used for pruritus, if needed.
Melasma is a benign skin condition characterized by hyperpigmentation of sun-exposed regions due to excess melanin production and deposition. The condition mainly affects women during their reproductive years, particularly those with darker skin tones. Hyperpigmented patches typically occur on the face, especially the cheeks, chin, forehead, and upper lip. The diagnosis is clinical. Management includes sun protection and topical depigmenting agents.
Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. A variety of organisms have been implicated, most commonly Staphylococcus aureus. Previously damaged joints (e.g., rheumatoid arthritis) are at the highest risk of infection. Patients present with a swollen, warm, and tender joint, most commonly involving the knee. Positive cultures from arthrocentesis are diagnostic, with antibiotic therapy tailored to the specific organism. Repeated joint aspiration, or surgical drainage, is required in some cases. If the joint space is infected with a prosthetic in place, debridement and prosthesis removal may also be required.
Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus, but a variety of organisms have been linked to osteomyelitis. The majority of patients present with pain, redness, and swelling of the affected site, and may have associated symptoms such as fever and chills. Laboratory values will demonstrate elevated WBC, CRP, and erythrocyte sedimentation rate (ESR) in most cases. The most sensitive and specific imaging modality to diagnose osteomyelitis is MRI. Management may require long-term antibiotics and potential surgical debridement.
Donovanosis (also known as granuloma inguinale) is an STD caused by Klebsiella granulomatis and is mainly seen in tropical regions. The condition is characterized by chronic, progressive, ulcerating disease mostly affecting the genital region. The patient presents with painless nodular lesions that ulcerate, commonly with a "beefy-red" base. There is no associated inguinal lymphadenopathy. Diagnosis is via history, clinical findings, and tissue smear or biopsy showing Donovan bodies, which are intracellular inclusion bodies inside macrophages. Treatment is with a prolonged course of antibiotics until lesions are healed, with monitoring for recurrence.
Albinism refers to a group of inherited disorders that result in the disruption of melanin production, causing hypopigmentation and visual impairment. The condition is classified according to the clinical phenotype. Oculocutaneous albinism results in hypopigmentation of the skin, eyes, and hair. Ocular albinism affects only the eyes. The diagnosis is clinical. Management is mainly supportive, with sun protection being a key component. Patients with albinism have an increased risk of skin cancer and require frequent skin examinations.
Influenza viruses are members of the Orthomyxoviridae family and the causative organisms of influenza, a highly contagious febrile respiratory disease. There are 3 primary influenza viruses (A, B, and C) and various subtypes, which are classified based on their virulent surface antigens, hemagglutinin (HA) and neuraminidase (NA). Influenza typically presents with a fever, myalgia, headache, and symptoms of an upper respiratory infection. Symptoms of gastroenteritis may also commonly occur in children. Influenza is usually a self-limiting condition, though viral or secondary bacterial pneumonia may complicate the disease. Management is generally supportive, although NA inhibitors can be helpful if initiated within 48 hours of infection. Prevention relies on the annual vaccination of the public and practicing good hygiene.
Haemophilus is a genus of Gram-negative coccobacilli, all of whose strains require at least 1 of 2 factors for growth (factor V [NAD] and factor X [heme]); therefore, it is most often isolated on chocolate agar, which can supply both factors. The most common pathogenic species is H. influenzae, which is transmitted through respiratory droplets and can cause epiglottitis, meningitis, otitis media, and pneumonia. H. ducreyi is transmitted through sexual contact and is the cause of chancroid, a type of genital ulcer.
Cushing's syndrome or hypercortisolism is a disorder characterized by features resulting from chronic exposure to excess glucocorticoids. Cushing's syndrome may be exogenous, due to chronic glucocorticoid intake, or endogenous, due to increased adrenal secretion of cortisol or adrenocorticotropic hormone (ACTH) production from the pituitary gland or ectopic sources. Exogenous or iatrogenic hypercortisolism is the most common cause. Typical clinical features of hypercortisolism include central obesity, thin and bruisable skin, abdominal striae, secondary hypertension, hyperglycemia, and proximal muscle weakness. The initial diagnostic approach is to establish hypercortisolism via urinary and salivary cortisol tests along with low-dose dexamethasone suppression test. Once the elevated cortisol levels are confirmed, the etiology is determined based on ACTH levels, confirmatory biochemical tests, and subsequent imaging studies. Treatment options depend on the cause, and include surgery and medical therapy.
Carcinoid tumors are small, well-differentiated, slow-growing neuroendocrine tumors (NET). Carcinoid syndrome describes the signs and symptoms associated with unregulated vasoactive hormone production by neuroendocrine tumors. Carcinoid tumors are most commonly found in the GI and bronchopulmonary tracts. Vasoactive substances produced by NET of the GI tract do not cause carcinoid syndrome until the tumors metastasize to the liver. Symptoms of carcinoid syndrome include flushing, diarrhea, and wheezing. Treatment consists primarily of surgical tumor resection and therapy with somatostatin analogs. Prognosis depends on the tumor location, aggressiveness, and overall disease burden.
Henoch-Schönlein purpura (HSP), also known as immunoglobulin A vasculitis, is an autoimmune small-vessel vasculitis that typically presents as a tetrad of abdominal pain, arthralgia, hematuria, and purpuric rash. The pathophysiology involves the deposition of IgA immune complexes in multiple vessels following a trigger (infection/environmental), and the symptoms depend on the tissues that are involved. The diagnosis is established clinically, but can be supported with laboratory studies and skin or kidney biopsy. Management is mostly supportive, but may involve steroids and immunosuppressants in more severe cases. Prognosis is usually excellent, but some patients may develop end-stage renal failure.
The hemophilias are a group of inherited, or sometimes acquired, disorders of secondary hemostasis due to deficiency of specific clotting factors. Hemophilia A is a deficiency of factor VIII, hemophilia B a deficiency of factor IX, and hemophilia C a deficiency of factor XI. Patients present with bleeding events that may be spontaneous or associated with minor or major trauma. Management is focused mainly on treatment of acute bleeding events and prevention of bleeding events via replacement of deficient factors.
Vitiligo is the most common depigmenting disorder and is caused by the destruction of melanocytes. The etiology is unknown; however, genetic and autoimmune factors may play a role. Patients present with hypo- or depigmented macules or patches which often occur on the face, hands, knees, and/or genitalia. The diagnosis is clinical. Management depends on the severity and can include sun protection, topical or oral steroids, topical calcineurin inhibitors, immunosuppressants, and phototherapy.
Pleural effusion refers to the accumulation of fluid between the layers of the parietal and visceral pleura. Common causes of this condition include infection, malignancy, autoimmune disorders, or volume overload. Clinical manifestations include chest pain, cough, and dyspnea. Imaging can confirm the presence of a pleural effusion, and pleural fluid analysis can help in the evaluation of an etiology. Management is dependent on the underlying condition and whether the effusion is causing respiratory distress. Drainage of the effusion may provide symptomatic relief.
Measles (also known as rubeola) is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae and the genus Morbillivirus. It is highly contagious and spreads only among humans by respiratory droplets or direct-contact transmission from an infected person. Typically a disease of childhood, measles classically starts with cough, coryza, and conjunctivitis, followed by a maculopapular rash. Complications include diarrhea, pneumonia, and encephalitis. Measles can be prevented through vaccination, and thanks to this, had largely been eradicated until recent years. Most cases are managed with supportive care, although in select patients, antivirals can be indicated.
Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Osteoclastic activity results in bone resorption, bone pain, pathologic fractures, and metabolic disturbances. Excessive secretion of antibodies results in proteinuria and associated kidney damage as well as production and tissue deposition of amyloid fibrils. Metabolic disturbances combined with tissue amyloid deposition cause end-organ damage. Diagnosis is established by plasma electrophoresis and bone marrow biopsy. Treatments to slow down the disease progression are available; however, there is no cure for MM. The median survival is approximately 3 years.
Erectile dysfunction (ED) is defined as the inability to achieve or maintain a penile erection, resulting in difficulty to perform penetrative sexual intercourse. Local penile factors and systemic diseases, including diabetes, cardiac disease, and neurological disorders, can cause ED. Diagnosis is via physical exam and history. Management is guided by clearly discussing patient expectations after explaining the benefits and risks. Treatment includes conservative management with lifestyle modifications, oral medications, and injectables. Invasive surgical penile implants may be considered when conservative measures fail. Ultimately, both the patient and partner must be in tune with the treatment modalities to optimize their overall satisfaction.
Hypersensitivity pneumonitis (HP), previously called extrinsic allergic alveolitis, is an immunologically induced inflammatory disease affecting the alveoli, bronchioles, and lung parenchyma. It is caused by repeated inhalation of an inciting agent in a susceptible host that triggers first a type III (complement-mediated) hypersensitivity reaction in the acute phase and then a type IV (delayed) reaction in the subacute and chronic phases. The clinical presentation of acute HP includes cough, fever, and malaise, while subacute and chronic forms present as insidious onset of a cough and dyspnea over weeks to months. Diagnosis is aided by high-resolution CT scans and bronchoalveolar lavage. Management includes avoiding the inciting agent and administration of steroids in subacute and chronic cases. Early treatment has a good prognosis, but long-term exposure can cause permanent scarring and fibrosis.
Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of mental retardation. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems. Characteristic traits include upslanting, almond-shaped eyes with skin covering the inner aspects, broad flattened nasal bridge, small rounded ears, and small mouth with large tongue. Screening for Down syndrome occurs during the 1st and 2nd trimesters of pregnancy and includes both blood tests and prenatal ultrasonography. Ultimately, karyotyping confirms diagnosis in the prenatal or postnatal period. There is no cure for Down syndrome. Treatment is based on the clinical manifestations present; it includes a strong support system and early intervention programs to help with education and development.
Gonorrhea is a sexually transmitted infection (STI) caused by the gram-negative bacteria Neisseria gonorrhoeae (N. gonorrhoeae). Gonorrhea may be asymptomatic but commonly manifests as cervicitis or urethritis with less common presentations such as proctitis, conjunctivitis, or pharyngitis. Without antibiotic treatment, complications can occur. Complications for men may include epididymitis, prostatitis, balanitis, and periurethral abscess. Women may develop pelvic inflammatory disease, which can cause perihepatitis and fertility issues. Disseminated gonococcal infection is associated with fever, dermatitis, tenosynovitis, septic arthritis, and (rarely) endocarditis or meningitis. Gonorrhea diagnosis is made by microscopy, culture, or nucleic acid amplification tests. Management generally involves ceftriaxone, but treatment with doxycycline should be pursued if a coinfection with Chlamydia trachomatis (C. trachomatis) is not excluded.
Sarcoidosis is a multisystem inflammatory disease that causes noncaseating granulomas. The exact etiology is unknown. Sarcoidosis usually affects the lungs and thoracic lymph nodes, but it can also affect almost every system in the body, including the skin, heart, and eyes, most commonly. Acutely, sarcoidosis presents with lymphadenopathy, fever, malaise, joint pains, a panniculitis on the shins known as erythema nodosum, and occasionally cough and shortness of breath. Chronic pulmonary sarcoidosis presents with an insidious onset of dyspnea, cough, chest pain, and a variety of other symptoms depending on the organ systems involved. Diagnosis often requires a biopsy of the granulomas. Management includes observation, NSAIDs, glucocorticoids, and potentially one of several steroid-sparing agents. Acute sarcoidosis is usually self-limiting with an excellent prognosis, but chronic sarcoidosis can lead to severe pulmonary fibrosis.
Organisms can be mostly classified into 2 groups, prokaryotes and eukaryotes, which have fundamental differences at the cellular level. Prokaryotes are unicellular organisms that include 2 of the 3 domains of life: bacteria and archaea. Eukaryotes can be single-celled or multicellular organisms and include plants, animals, fungi, and protozoa. Prokaryotic cells consist of a single cytoplasm-filled compartment enclosed by a cell membrane and cell wall, while eukaryotic cells contain a well-organized nucleus contained by a membrane, along with other membrane-bound organelles.
Molluscum contagiosum is a viral infection limited to the epidermis and is common in children below 5 years of age. Lesions appear as grouped, flesh-colored, dome-shaped papules with central umbilication. Molluscum contagiosum is mild in immunocompetent patients and self resolves within months. Immunocompromised individuals present with extensive lesions and systemic disease, which require treatment. Molluscum contagiosum is highly transmissible; therefore, patient education is key in its management. Cryotherapy with liquid nitrogen is the 1st-line treatment.
Bullous pemphigoid and pemphigus vulgaris are two different blistering autoimmune diseases. In bullous pemphigoid, autoantibodies attack the hemidesmosomes, which connect epidermal keratinocytes to the basement membrane. This attack results in large, tense subepidermal blisters. In pemphigus vulgaris, autoantibodies attack the desmosomal proteins, which connect the keratinocytes to one another. This attack results in a more severe, potentially fatal condition with fragile, flaccid blisters, usually with significant mucosal involvement. Diagnosis is made with biopsy and IF staining to identify and localize the antibodies. Management involves immunosuppression with corticosteroids and other steroid-sparing immunomodulatory agents.
Angioedema is a localized, self-limited (but potentially life-threatening), nonpitting, asymmetrical edema occurring in the deep layers of the skin and mucosal tissue. The common underlying pathophysiology involves inflammatory mediators triggering significant vasodilation and increased capillary permeability. Clinically, angioedema presents with swelling around the eyes, lips, tongue, mouth, bowel wall, extremities, or genitalia. Angioedema may also compromise the airway. Urticaria will be present when the angioedema is mediated by mast cells, but not when it is due to increases in bradykinin. Diagnosis is usually clinical but additional testing may include skin/serum testing for specific antigens and C4 level assessment. Management depends on the underlying mechanism but may include treatment for anaphylaxis, removing any offending agents, antihistamines, glucocorticoids, and/or therapies that target bradykinin.
Abnormal uterine bleeding is the medical term for abnormalities in the frequency, volume, duration, and regularity of the menstrual cycle. Abnormal uterine bleeding is classified using the acronym PALM-COEIN, with PALM representing the structural causes and COEIN indicating the non-structural causes. Etiologies include polyp (P), adenomyosis (A), leiomyoma (L), malignancy/hyperplasia (M), coagulopathy (C), ovulatory dysfunction (O); endometrial pathology including endometritis and atrophy (E), iatrogenic causes (I), and etiologies not otherwise classified (N). Diagnosis usually requires careful history-taking and examination, basic laboratory work, transvaginal ultrasound, and endometrial biopsy based on age and risk factors. Management depends on the underlying etiology, but often includes oral contraceptive pills, levonorgestrel-containing intrauterine devices, and surgery.
Syphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Primary syphilis begins with a chancre, a painless ulcer on the genitals. Progression to secondary syphilis manifests as a generalized maculopapular rash, which includes the palms and soles. The development of tertiary syphilis can cause severe neurologic (neurosyphilis), cardiovascular, and/or gummatous disease. The diagnosis is through both treponemal and nontreponemal testing. Penicillin G is the antibiotic of choice. The duration of management varies based on the stage of the disease.
Alcoholic liver disease is a spectrum of disorders ranging from fatty liver to cirrhosis secondary to chronic alcohol abuse. Excessive and prolonged consumption of alcohol results in impairment of the lipolysis pathway, causing inflammatory changes within the hepatocytes. Patients typically present during the hepatitis stage with jaundice, fever, and abdominal pain. Diagnosis is based on a history of alcohol abuse and confirmed by laboratory derangement with an AST/ALT ratio > 2. Alcoholic liver disease carries a high mortality rate if patients present with severe hepatitis. Management aims at alcohol abstinence for reversal (at certain stages) and addressing contributing factors (such as viral infections or drugs) to minimize damage to the hepatocytes. Approximately 10% of patients regress with alcohol abstinence during the hepatitis stage. Cirrhosis is frequently irreversible.
Menopause is a physiologic process in women characterized by the permanent cessation of menstruation that occurs after the loss of ovarian activity. Menopause can only be diagnosed retrospectively, after 12 months without menstrual bleeding. During the menopausal transition, reproductive hormones can fluctuate significantly, leading to symptoms that include hot flushes, sleep and mood disturbances, and vaginal dryness. In postmenopausal woman, low estrogen levels contribute to an increased risk for cardiovascular disease, osteoporosis, and sexual dysfunction due to vulvovaginal atrophy. For some women, symptoms negatively affect their quality of life and treatment is warranted. Management usually involves hormone replacement therapy (HRT), but other treatment options also exist.
Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis most often presents clinically with frequent fractures and loss of vertebral height. Diagnosis is established by measuring bone mineral density. Management includes lifestyle modifications, maintaining adequate levels of calcium and vitamin D, and the use of bisphosphonates.
Intestinal malrotation is a congenital anomaly that results from failure of the GI tract to undergo normal rotation around the mesenteric vessels during embryologic development. This condition can result in several anatomic patterns characterized by abnormal location and attachments of the abdominal cavity's intestines. These anomalies can be clinically silent or present with a number of complications, the most catastrophic of which is midgut volvulus. Intestinal malrotation usually presents in infancy as an acute onset of bilious vomiting. Definitive diagnosis is established with the upper GI series and the treatment is emergent surgery.
Primary ovarian insufficiency (POI) is a condition resulting from the depletion or dysfunction of the ovarian follicles, leading to cessation of ovulation and menses before age 40. Primary ovarian insufficiency is primarily idiopathic, but it can also be seen in association with chromosomal and genetic defects, including Turner syndrome (45,X karyotype) and FMR1 premutation. Patients present with signs and symptoms of menopause prior to age 40, including oligomenorrhea or amenorrhea, vaginal dryness (often leading to dyspareunia), and infertility. Key laboratory findings include elevated follicle-stimulating hormone (FSH) and low estrogen levels. Once the diagnosis of POI is made, the patient should be screened for autoimmune adrenal antibodies, and a karyotype, FMR1 premutation screen, and baseline DEXA scan should be obtained. Management includes hormone replacement therapy (HRT), addressing fertility concerns as desired, and psychological support.
Pheochromocytoma is a catecholamine-secreting tumor derived from chromaffin cells. The majority of tumors originate in the adrenal medulla, but they may also arise from sympathetic ganglia (also referred to as paraganglioma). Symptoms are associated with excessive catecholamine production and commonly include hypertension, tachycardia, headache, and sweating. Pheochromocytomas are frequently familial and associated with genetic syndromes. Approximately 90% of pheochromocytomas are benign and surgical resection is the only curative treatment. Prognosis is generally good for benign, sporadic tumors that have been completely resected. Familial forms are associated with higher recurrence rates and malignant potential.
Truncus arteriosus (TA) is a congenital heart defect characterized by the persistence of a common cardiac arterial trunk tract that fails to divide into the pulmonary artery and aorta during embryonal development. Truncus arteriosus is a rare congenital malformation with a high mortality rate within the 1st 5 weeks of life if not managed promptly. Neonates may be asymptomatic at birth but invariably develop respiratory distress and heart failure. Diagnosis is commonly made prenatally through screening ultrasounds. In the event of a missed antenatal diagnosis, TA is confirmed through an echocardiogram. Treatment involves medical stabilization immediately after birth, followed by definitive surgery. With appropriately timed management, the prognosis is excellent.
Coarctation of the aorta is a narrowing of the aorta between the aortic arch and the iliac bifurcation commonly around the point of insertion of the ductus arteriosus. Coarctation of the aorta is typically congenital and the clinical presentation depends on the age of the patient. Neonates present with heart failure upon the closure of the ductus arteriosus, while children and adults present with hypoperfusion and/or hypertension. Classic findings on physical exam include radio-/brachio-femoral delay and decreased blood pressure in the lower limbs. Diagnosis is confirmed by echocardiogram. Patients should be surgically managed as early as possible to avoid complications of hypertension. Close follow-up is required as the risk of hypertension and re-coarctation remain.
Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder that is caused by a mutation in the DMD gene. The mutation leads to the production of abnormal dystrophin, resulting in muscle-fiber destruction and replacement with fatty or fibrous tissue. Affected individuals present with progressive proximal muscle weakness leading to the eventual loss of ambulation, as well as contractures, scoliosis, cardiomyopathy, and respiratory failure. A marked elevation in CK may be observed. Genetic testing is used to confirm the diagnosis. Management is supportive and aimed at slowing disease progression and complications. Duchenne muscular dystrophy is fatal with a life expectancy of about 20 years of age.
Erysipelas is a bacterial infection of the superficial layer of the skin extending to the skin's superficial lymphatic vessels. This infection presents as a raised, well-defined, tender, and bright red rash. Typically on the legs or face, but erysipelas can occur anywhere on the skin. This infection occurs when bacteria enter through the points of skin breakdown. The most common bacteria causing this infection is group A Streptococci (especially Streptococcus pyogenes). Diagnosis is based mostly on the history and physical exam. Management includes antibiotics.
Necrotizing fasciitis is a life-threatening infection that causes rapid destruction and necrosis of the fascia and subcutaneous tissues. Patients may present with significant pain out of proportion to the presenting symptoms and rapidly progressive erythema of the affected area. Most patients will also have systemic signs of infection, including fever, hypotension, altered mental status, and multisystem organ failure. The diagnosis is primarily clinical since patients can quickly progress to septic shock without source control. This type of infection is a surgical emergency and requires emergent surgical debridement, parenteral antibiotics, and close hemodynamic monitoring.
Cutaneous squamous cell carcinoma (cSCC) is caused by malignant proliferation of atypical keratinocytes. This condition is the 2nd most common skin malignancy and usually affects sun-exposed areas of fair-skinned patients. The cancer presents as a firm, erythematous, keratotic plaque or papule. Histopathologic examination should be done for all suspected cases, as many lesions, such as actinic keratosis, mimic the appearance of SCC. Surgical excision is the mainstay of treatment. Overall prognosis is excellent for completely excised lesions, but certain high-risk features may predispose to metastatic disease and poor outcomes.
Benign or nonacute scrotal masses are represented by hydroceles, varicoceles, and spermatoceles. Key components to evaluation are physical exam and scrotal ultrasound. Hydroceles represent extra fluid in the tunica vaginalis, leading to a swollen scrotum. Varicoceles have a dilatation of the pampiniform venous plexus, giving the “bag of worms” appearance on exam. Spermatoceles present as an epididymal cyst, commonly arising from the head of the epididymis. Hydroceles, varicoceles, and spermatoceles are usually asymptomatic and do not require treatment unless they are causing pain or other complications.
Cervical cancer, or invasive cervical carcinoma (ICC), is the 3rd most common cancer in women in the world, with > 50% of the cases being fatal. In the United States, ICC is the 13th most common cancer and the cause of < 3% of all cancer deaths due to the slow progression of precursor lesions and, more importantly, effective cancer screening. There are 2 major histologic types of ICC: squamous cell carcinoma (SCC) and adenocarcinoma. High-risk human papillomaviruses (hrHPVs) cause > 99% of SCCs and > 85% of adenocarcinomas. Early cervical neoplasia is asymptomatic, and diagnosis is made using routine screening methods, including the cervical Papanicolaou test with cytology, hrHPV testing, and biopsy. Treatment of precursor or dysplastic lesions depends on the severity of the dysplasia and the age of the patient. Management of ICCs depends on the stage and varies from excisional biopsy by cervical cone biopsy for microinvasive ICC to radical hysterectomy for more advanced cases. If there is extracervical spread, radiation and chemotherapy would be recommended.
Rickets and osteomalacia are disorders of decreased bone mineralization. Rickets affects the cartilage of the epiphyseal growth plates in children, while osteomalacia affects the sites of bone turnover in children and adults. Although most cases of rickets and osteomalacia are due to vitamin D deficiency, other genetic and nutritional disorders as well as medications can cause these disorders. Rickets commonly presents with skeletal deformities and growth abnormalities, while osteomalacia can present with bone pain, difficulty with ambulation and pathologic fractures. Diagnosis is made based on a combination of clinical findings, laboratory tests and imaging. Treatment includes vitamin D, calcium, and phosphorus supplementation.
Systemic lupus erythematosus (SLE) is a chronic autoimmune, inflammatory condition that causes immune-complex deposition in organs, resulting in systemic manifestations. Women, particularly those of African American descent, are more commonly affected. The clinical presentation can vary greatly. Notable clinical features include malar rash, nondestructive arthritis, lupus nephritis, serositis, cytopenia, thromboembolic disease, seizures, and/or psychosis. Diagnosis is based on clinical criteria, and includes tests to determine ANAs, SLE-specific antibodies, and specific clinical findings. The goal of management is to control symptoms and prevent organ damage, using corticosteroids, hydroxychloroquine, and immunosuppressants.
Intussusception occurs when a part of the intestine (intussusceptum) telescopes into another part (intussuscipiens) of the intestine. The condition can cause obstruction and, if untreated, progress to bowel ischemia. Intussusception is most common in the pediatric population, but is occasionally encountered in adults. The pediatric patient typically presents with acute cyclical abdominal pain and vomiting, while adults present with symptoms of bowel obstruction. The diagnosis in children is frequently clinical but may be supported by an abdominal ultrasound showing a classic target sign. Management options in children include contrast or pneumatic enema, with surgical options reserved for failure of the non-operative measures, complications such as gangrene or perforation, and treatment of underlying pathology. In adult patients, surgery is usually required.
Pelvic inflammatory disease (PID) is defined as a polymicrobial infection of the upper female reproductive system. The disease can affect the uterus, fallopian tubes, ovaries, and adjacent structures. Pelvic inflammatory disease is closely linked with sexually transmitted diseases, most commonly caused by Chlamydia trachomatis and Neisseria gonorrhoeae, as well as organisms associated with bacterial vaginosis, such as Gardnerella vaginalis. Common symptoms are lower abdominal pain, cervical discharge, and irregular vaginal bleeding. Complications of PID can include ectopic pregnancy, chronic pelvic pain, and infertility. Diagnosis is primarily clinical in addition to PCR testing of cervical specimens and sometimes imaging or laparoscopy. Due to its polymicrobial nature, PID treatment is with combination antibiotic regimens.
Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Molecular profiling of the cancer provides further distinction of the tumor's biological behavior, prognosis, and treatment options. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Regional and metastatic spread cause additional symptoms and complications depending on the location and organ(s) affected. Related paraneoplastic syndromes include hypercalcemia, hyponatremia, Lambert-Eaton syndrome, Cushing's syndrome, polydermatomyositis, and dermatomyositis. Definitive diagnosis and staging are made by biopsy, genetic mutation with biomarker testing, and imaging. Management is guided by the cancer stage and associated molecular profile. Lung cancer carries an overall poor prognosis.
Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Deep vein thrombosis (DVT) is diagnosed in > 50% of patients presenting with symptoms, in whom the lower-extremity deep-venous system is the most common source of thrombus. Some individuals are asymptomatic, but the most common presenting symptom is dyspnea. The symptoms can be acute or chronic, and diagnosis is usually based on radiographic findings. Initial management is supportive and focuses on restoring oxygenation and hemodynamic stability. Both medical (systemic anticoagulants) and interventional therapies (catheter-based approach, surgery) are used to reestablish vessel patency.
Hemorrhoids are normal vascular cushions in the anal canal composed of dilated vascular tissue, smooth muscle, and connective tissue. They do not cause issues unless they are enlarged, inflamed, thrombosed, or prolapsed. Patients often present with rectal bleeding of bright red blood, or they may have pain, perianal pruritus, or a palpable mass. Risk factors include family history, low-fiber diet, and constipation. The two main types of hemorrhoids are external, usually with perianal pain, and internal, which are usually painless. The main diagnostic tools are history, physical exam, and endoscopic procedures if indicated for further investigation. If symptoms are acute, excision can be performed for external hemorrhoids. Otherwise, conservative management is recommended. Surgical methods are reserved for more severe hemorrhoids or those unresponsive to primary treatment.
Whipple's disease is a rare malabsorption syndrome with systemic manifestations (neurologic, cardiac, and musculoskeletal) caused by the bacterium Tropheryma whipplei. Patients often present with weight loss, diarrhea/steatorrhea, and arthralgias, as well as neurologic and cardiac manifestations. Whipple's disease is diagnosed with biopsy after the visualization of periodic acid–Schiff (PAS)-positive foamy macrophages in the involved tissues or with PCR for the bacterial DNA. It is managed with antibiotics, namely ceftriaxone or penicillin G and sulfamethoxazole.
Hypopituitarism is a condition characterized by pituitary hormone deficiency. This condition primarily results from a disease of the pituitary gland, but it may arise from hypothalamic dysfunction. Pituitary tumors are one of the most common causes. The majority of cases affect the anterior pituitary lobe (adenohypophysis), which accounts for 80% of the gland. The hormones produced from this lobe are growth hormone, follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone (TSH), adrenocorticotropic hormone, and prolactin. When the posterior lobe (neurohypophysis) is also damaged, loss of antidiuretic hormone and oxytocin occurs. All of these hormones regulate the activities of different organs, and thus the effects of pituitary hypofunction are multisystemic. The diagnosis is made through a combination of clinical findings, hormone levels, provocation tests, and brain imaging. Treatment is hormone replacement and addressing the etiology.
Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Associated symptoms, including fever, nausea and vomiting, weight loss, and bloody stools are also important to elicit from the history. Most causes of acute diarrhea are infectious and do not require additional workup. Since diarrhea is usually a self-limited condition, management is generally supportive. However, chronic diarrhea can require laboratory studies, stool studies, imaging, or procedures to determine the cause. Management ultimately hinges on treating the underlying pathology, though symptomatic and empiric therapies may be utilized under the right circumstances.
Chronic venous disease is a spectrum of disorders characterized by venous dilation and/or abnormal vein function in the lower extremities resulting from venous hypertension. "Chronic venous insufficiency" refers to the more severe forms of chronic venous disease. Skin changes typically distinguish chronic venous insufficiency from milder forms of venous disease (like varicose veins) and include skin pigmentation, stasis dermatitis, lipodermatosclerosis, and eventually, the development of ulcers. Diagnosis is usually based on physical exam findings alone, although venous duplex ultrasonography can provide additional information about the etiology, location, and extent of disease. The mainstay of management is compression therapy. A variety of surgical options also exist, including ablation, sclerotherapy, and valve repair. Venous ulcers are common as the disease progresses and are often very difficult to treat.
Aplastic anemia (AA) is a rare, life-threatening condition characterized by pancytopenia and hypocellularity of the bone marrow (in the absence of any abnormal cells) reflecting damage to hematopoietic stem cells. Aplastic anemia can be acquired or inherited, however, most cases of AA are acquired and caused by autoimmune damage to hematopoietic stem cells. Specifically known acquired causes and associations of AAs include medications, chemicals, high doses of whole-body radiation, viral infections, immune diseases, and pregnancy. Inherited or constitutional syndromes associated with AA include Fanconi anemia, dyskeratosis congenita, and Down syndrome. Therapies include transfusion support, immunosuppression, and bone marrow transplantation.
The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, which articulate with each other at the proximal and distal tibiofibular joints. The muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia and exert their action on the ankle, foot, and toes.
The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. The thigh is supplied primarily by the femoral artery and its branches, drained by deep and superficial venous networks, and innervated by branches of the lumbar and sacral plexuses.
Crush syndrome encompasses the systemic manifestations that result from a crush (or traumatic compression) injury. Compartment syndrome and/or rhabdomyolysis can also occur in crush syndrome. Systemic effects include the development of renal failure due to toxins released from damaged muscles, hypovolemia, and acidosis. Other features include arrhythmias from the electrolyte imbalances, ARDS from the inflammatory response, and disseminated intravascular coagulation from liberated thromboplastin. Field management with intravenous fluids and extrication is crucial in reducing the risk of death. Inpatient care requires a multidisciplinary team focused on continued hydration, reducing complications or further injury, and determining the need for operative intervention.
Fibrocystic change of the breast is a non-specific term referring to several types of benign breast conditions. These are non-proliferative lesions, which include cystic and fibrous tissue formation. Fibrocystic changes are seen in up to 50–60% of women, most commonly between 30–50 years of age. Changes are stimulated by both estrogen and progesterone, and often diminish or resolve with menopause. Patients typically present with a breast mass, “lumpy” or firm breasts, and/or cyclic breast pain. The work-up involves imaging, with mammogram or ultrasound, and biopsy (if needed) to exclude malignancy. Management includes observation, supportive measures, and altering hormone therapy, as needed. These changes do not appear to significantly increase the risk for breast cancer.
Pierre Robin sequence, also known as Pierre Robin syndrome or simply Robin sequence, is a condition in infants that is characterized by a smaller-than-normal mandible, a tongue that retracts back into the throat, and difficulty breathing. The exact etiology of the Pierre Robin sequence is unknown, although some contributing factors have been identified. The abnormal development of the lower jaw during gestation, along with certain genetic mutations, can be the first of a series of steps leading to breathing and feeding problems in the neonate.
Androgen insensitivity syndrome (AIS) is an X-linked recessive condition in which a genetic mutation affects the function of androgen receptors, resulting in complete (CAIS), partial (PAIS), or mild (MAIS) resistance to testosterone. All individuals with AIS have a 46,XY karyotype; however, phenotypes vary and include phenotypic female, virilized female, undervirilized male, and phenotypic male individuals. Androgen insensitivity syndrome always leads to infertility. Hormone analysis, imaging, and genetic testing help make the diagnosis. Management of AIS varies depending on the degree of androgen sensitivity, phenotype, and gender identity, and may involve hormone-replacement therapy and surgery to correct anatomical anomalies of the reproductive and genital structures.
Ventricular septal defects (VSDs) are congenital cardiac malformations that feature an abnormal communication between the right and left ventricles. Presenting both in isolation or as part of a more complex disease, VSD is the most common congenital heart defect. While the degree of severity depends on the size of the defect, VSDs are classified on the basis of the anatomical location of the defect. Patients may be asymptomatic with smaller defects, whereas larger defects can present with respiratory or heart failure during infancy or childhood. A common clinical sign is a holosystolic murmur audible at the left sternal border. Diagnosis, both pre- and post-natal, is confirmed by echocardiogram. The majority of small VSDs close spontaneously, but those that are larger and symptomatic require medical stabilization followed by surgical repair.
Testicular torsion is the sudden rotation of the testicle, specifically the spermatic cord, around its axis in the inguinal canal or below. The acute rotation results in compromised blood flow to and from the testicle, which puts the testicle at risk for necrosis. Quick diagnosis and intervention is key to saving the affected testicle. Emergent surgical exploration with subsequent orchidopexy is required. Ultrasound or manual detorsion should not delay definitive care.
Prostatitis is inflammation or an irritative condition of the prostate that presents as different syndromes: acute bacterial, chronic bacterial, chronic prostatitis/chronic pelvic pain, and asymptomatic. Bacterial prostatitis is easier to identify clinically and the management (antibiotics) is better established. Whether the condition is in an acute or chronic state determines the length of antibiotic treatment. The main diagnostic tools are history, physical examination, and work-up investigating the sources of infection (urinalysis and culture). Digital rectal examination is only recommended in patients with chronic prostatitis and not in acute bacterial prostatitis due to the risk of sepsis. Chronic pelvic pain syndrome is a diagnosis of exclusion and requires multimodal pain management with established patient expectations. The asymptomatic type is an incidental finding that is recognized when a patient has other urologic issues.
Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Systemic inflammation can lead to extraarticular manifestations such as rheumatoid nodules, interstitial lung disease, Felty syndrome, and pericarditis. Prolonged and severe disease can lead to irreversible joint deformities. Diagnosis is based on strong clinical suspicion and confirmed by the presence of rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, and characteristic imaging. Management involves long-term disease-modifying antirheumatic drugs (DMARDs), biologic agents, and physical therapy. Glucocorticoids and nonsteroidal antiinflammatory drugs (NSAIDs) are the treatment of choice for acute exacerbation.
Melanoma is a malignant tumor arising from melanocytes, the melanin-producing cells of the epidermis. These tumors are most common in fair-skinned individuals with a history of excessive sun exposure and sunburns. Melanomas usually present as pigmented skin lesions, but they can occur on mucosal surfaces, such as in the eyes, anal canal, and genital regions. Common findings may include Asymmetry of the lesion, irregular Border, varying Color, > 6 mm Diameter, and Evolving features (ABCDE). Definitive diagnosis is established with biopsy. Treatment relies primarily on surgical excision. The prognosis is very good for early-stage lesions but quite dismal for metastatic disease. Of all the skin malignancies, melanoma generally carries the worst prognosis.
An important complication of anesthesia is malignant hyperthermia, an autosomal dominant disorder of the regulation of calcium transport in the skeletal muscles resulting in a hypermetabolic crisis. Malignant hyperthermia is marked by high fever, muscle rigidity, rhabdomyolysis, and respiratory and metabolic acidosis. The mortality rate reaches 90% if not quickly identified and treated. Management involves stopping the offending agent and administering dantrolene.
Ankylosing spondylitis (also known as Bechterew’s disease or Marie-Strümpell disease) is a seronegative spondyloarthropathy characterized by chronic and indolent inflammation of the axial skeleton. Severe disease can lead to fusion and rigidity of the spine. Ankylosing spondylitis is most often seen in young men and is strongly associated with HLA-B27. Patients will have progressive back pain (which improves with activity), morning stiffness, and decreased range of motion of the spine. Extra-articular manifestations include fatigue, enthesitis, anterior uveitis, restrictive lung disease, and inflammatory bowel disease. The diagnosis is based on the clinical history, physical exam, and imaging demonstrating sacroiliitis and bridging syndesmophytes. Most patients are managed with physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDs). More severe cases may require tumor necrosis factor-alpha inhibitors or surgery.
Acute rheumatic fever (ARF) is an autoimmune inflammatory process that usually follows Streptococcal pharyngitis. Acute rheumatic fever usually occurs 2–4 weeks after an untreated infection and affects the heart, skin, joints, and nervous system. This condition commonly presents with fever, arthritis of the large joints, pancarditis and sometimes rash and neurologic manifestations. The diagnosis is made clinically based on the Jones criteria, and confirmed with serologic tests. Prevention of ARF is the key treatment strategy, and is based on timely antibiotic treatment of the primary infection as well as antibiotic prophylaxis of recurrent episodes. Management of acute episodes is largely supportive and includes anti-inflammatory medications. The most serious complication of ARF is development of rheumatic heart disease, which most commonly manifests as mitral valve stenosis.
Congenital adrenal hyperplasia (CAH) consists of a group of autosomal recessive disorders that cause a deficiency of an enzyme needed in cortisol, aldosterone, and androgen synthesis. The most common subform of CAH is 21-hydroxylase deficiency, followed by 11β-hydroxylase deficiency. Clinical manifestations depend on the specific enzyme affected. Notably, CAH is the most common cause of ambiguous genitalia in genotypic female individuals. All forms of CAH cause low levels of cortisol, high levels of adrenocorticotropic hormone (ACTH), and adrenal hyperplasia. Laboratory studies help confirm the diagnosis. Lifelong glucocorticoid replacement is needed, and surgical correction of ambiguous genitalia is often performed.
Epididymitis and orchitis are characterized by acute inflammation of the epididymis and the testicle, respectively, due to viral or bacterial infections. Patients typically present with gradually worsening testicular pain and scrotal swelling along with systemic symptoms such as fever, depending on severity. Patients with concomitant sexually transmitted diseases (STDs) may present with lower urinary tract symptoms. Diagnosis is based on clinical findings and urinalysis with culture. Scrotal ultrasound may show increased blood flow to the affected epididymis or testicle. Treatment is with empiric gram-negative coverage antibiotics and culture-directed therapy. Supportive care includes scrotal support and non-steroidal anti-inflammatory drugs.
Rhabdomyolysis is characterized by muscle necrosis and the release of toxic intracellular contents, especially myoglobin, into the circulation. Rhabdomyolysis can result from trauma or direct muscle injuries; however, non-exertional and non-traumatic etiologies (heatstroke, immobilization, medication side effects) can also lead to muscle breakdown. The classic triad of symptoms includes myalgia, weakness, and tea-colored urine, but the presentation can be nonspecific. History and work-up generally point to diagnosis based on elevated creatine kinase levels, abnormal electrolytes with possible renal failure, and dark urine without red blood cells (indicating myoglobinuria). Management of rhabdomyolysis is by using intravenous fluid resuscitation.
The ductus arteriosus (DA) is a fetal blood vessel connecting the left pulmonary artery to the aorta. The DA allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent ductus arteriosus is twice as common in girls (especially premature infants) and causes a continuous machinery-like murmur on clinical examination. Patent ductus arteriosus may be associated with other cardiac defects; an echocardiogram can confirm the diagnosis. Treatment aims at closure of the remnant structure either through pharmacological or surgical means.
Stomatitis is a general term referring to inflammation of the mucous membranes of the mouth, which may include sores. Stomatitis can be caused by infections, autoimmune disorders, allergic reactions, or exposure to irritants. The typical presentation may be either solitary or a group of painful oral lesions. The etiology of the lesion is diagnosed based on appearance and associated symptoms. Treatment involves symptomatic relief, but infectious causes may require antivirals/antibiotics and autoimmune etiologies may require steroid therapy.
Mastitis is inflammation of the breast tissue with or without infection. The most common form of mastitis is associated with lactation in the first few weeks after birth. Non-lactational mastitis includes periductal mastitis and idiopathic granulomatous mastitis (IGM). Lactational mastitis is most commonly caused by Staphylococcus aureus that is introduced into the breast milk during breastfeeding. The etiology of non-lactational mastitis is poorly understood, but periductal mastitis is commonly associated with smoking, and IGM is frequently associated with Corynebacterium. Patients present with edema, erythema, tenderness, and, possibly, a mass in the breast. Diagnosis is usually clinical, although ultrasound, cultures, and biopsy may be required in some cases. Management involves antibiotics, analgesics, drainage of any abscesses, and surgical duct excision for periductal mastitis.
Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%‒10% of women in the age group. Characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction, PCOS increases a woman’s risk for infertility, endometrial hyperplasia or carcinoma, and cardiovascular disease. The pathophysiology is incompletely understood but thought to have a multifactorial genetic basis causing altered pulsatile release of gonadotropin-releasing hormone (GnRH), as well as increases in luteinizing hormone (LH), androgens, estrogen, and insulin: The result is chronic anovulation and hirsutism, which define the condition. Diagnosis is one of exclusion; therefore, other causes of abnormal uterine bleeding and hirsutism must be ruled out. Management includes attempting to restore normal ovulation through weight loss, oral contraceptive pills (OCPs), and fertility assistance.
Mesenteric ischemia is a rare, life-threatening condition caused by inadequate blood flow through the mesenteric vessels, which results in ischemia and necrosis of the intestinal wall. Mesenteric ischemia can be either acute or chronic. Acute mesenteric ischemia may be caused by an arterial embolism, thrombosis, non-occlusive disease, or venous thrombosis. Chronic mesenteric ischemia is most commonly caused by atherosclerotic disease. Patients present with abdominal pain out of proportion to the abdominal examination. Peritonitis, sepsis, and hematochezia are concerning for bowel infarction. Computed tomography (CT) with angiography of the abdomen and pelvis is the diagnostic modality of choice. Management is often surgical and focuses on re-establishing blood flow to the intestines, as well as resection of any nonviable bowel.
A burn is a type of injury to the skin and deeper tissues caused by exposure to heat, electricity, chemicals, friction, or radiation. Burns are classified according to their depth as superficial (1st-degree), partial-thickness (2nd-degree), full-thickness (3rd-degree), and 4th-degree burns. Management is greatly dependent on the extent of surface area affected and the depth of the burns. Management involves fluid resuscitation, adequate analgesia, and appropriate wound care with the goal of preventing opportunistic infection.
Breast cancer is the most common cancer in women and the 2nd-leading cause of cancer-related deaths in women in the United States. Early detection and improved pathology-specific treatments have resulted in a decrease in death rates. Several organizations provide recommendations regarding screening for specific age and risk groups. Screenings include breast examination, mammography, magnetic resonance imaging (MRI), and ultrasound (US).
The term vulvovaginitis is used to describe an acute inflammation of the vulva and vagina. Vulvovaginitis can be caused by several infectious and non-infectious etiologies, and results from disruption of the normal vaginal environment. Common signs and symptoms include pain, pruritis, erythema, and edema of the affected region, as well as vaginal discharge and dyspareunia. The diagnosis is based on the clinical presentation, physical examination findings, and inspection of vaginal secretions. Management depends on the etiology, including antimicrobials for infectious causes.
Lung cancer is the leading cause of cancer-related death in the United States, with 90% of cases being fatal. The vast majority of cases are associated with smoking, and thus smoking cessation is encouraged to reduce a patient’s lifetime risk. Annual screening with low-dose computed tomography is recommended for early detection in patients 50–80 years of age with a significant smoking history. This screening program has been shown to significantly reduce mortality.
Alopecia is the loss of hair in areas anywhere on the body where hair normally grows. Alopecia may be defined as scarring or non-scarring, localized or diffuse, congenital or acquired, reversible or permanent, or confined to the scalp or universal; however, alopecia is usually classified using the 1st 3 factors. The etiologies of alopecia are usually divided into disorders in which the hair follicle is abnormal or damaged and those in which the hair follicle is normal but the cycling of hair growth is abnormal. The most common presentations are androgenetic hair loss, alopecia areata, traction alopecia, tinea capitis, and telogen effluvium. Diagnosis is made through a positive medical history and physical exam findings. Treatment depends on the type and potential for regrowth.
Hypoplastic left heart syndrome (HLHS) is a congenital heart defect that consists of the underdevelopment, or hypoplasia, of the left side of the heart in various degrees. The most notable feature of HLHS is the reduced size and functionality of the left ventricle (LV). Also, HLHS is associated with stenosis, hypoplasia, or atresia of the vessels or atrioventricular valves on the left side of the heart. A mixture of genetic factors and altered fetal blood flow causes HLHS. Hypoplastic left heart syndrome presents once the ductus arteriosus closes physiologically as tachypnea, cyanosis, heart failure, and cardiogenic shock. Diagnosis can be made pre- or postnatally via echocardiogram. Once detected, surgical treatment is the 1st-line therapy, done in 3 stages.
A hemothorax is a collection of blood in the pleural cavity. Hemothorax most commonly occurs due to damage to the intercostal arteries or from a lung laceration following chest trauma. Hemothorax can also occur as a complication of disease, or hemothorax may be spontaneous or iatrogenic. Large hemothoraces can be life-threatening by leading to lung collapse. Patients present with shortness of breath and chest pain. Physical exam findings include hypotension, tachycardia, decreased lung sounds, and dullness on percussion of the chest. Diagnosis is by upright chest X-ray. Management is with tube thoracostomy drainage, video-assisted thoracoscopic surgery (VATS), or thoracotomy when massive hemothorax or persistent bleeding is present.
Blunt chest trauma is a non-penetrating traumatic injury to the thoracic cavity. Thoracic traumatic injuries are classified according to the mechanism of injury as blunt or penetrating injuries. Different structures can be injured including the chest wall (ribs, sternum), lungs, heart, major blood vessels, and the esophagus. The extent and specific type of thoracic traumatic injury can be identified by a proper history and physical examination supported by adequate imaging studies. Management depends on the specific type of injury.
Traumatic injuries to the genitourinary (GU) tract include injuries to the kidneys, ureter, bladder, urethra, or genitals. Typically, injuries to the GU tract alone are not life threatening, but can be associated with other potentially more significant injuries. The GU system is divided into the upper GU tract (kidneys and ureters) and the lower GU tract (bladder, urethra, and external genitalia). Mechanisms include blunt and penetrating injuries. Diagnosis relies on thorough physical exam and imaging. Management depends on the severity of injury and ranges from simple observation and supportive measures to major surgical interventions. Timely diagnosis and intervention are crucial for preventing complications and ensuring optimal outcomes.
Treponema is a gram-negative, microaerophilic spirochete. Owing to its very thin structure, it is not easily seen on Gram stain, but can be visualized using dark-field microscopy. This spirochete contains endoflagella, which allow for a characteristic corkscrew movement. The bacteria are able to avoid immune recognition and phagocytosis by forming a protective coating with fibronectin. Humans are the only reservoir and transmission is through human-to-human contact. The most common species involved in human disease is Treponema pallidum subspecies pallidum, which is the causative agent of syphilis. Other clinically relevant species include T. pallidum pertenue, T. pallidum endemicum, and T. carateum. These are the causative organisms for yaws, bejel, and pinta, respectively.
Cryptorchidism is one of the most common congenital anomalies in young boys. Typically, this asymptomatic condition presents during a routine well-child examination where 1 or both testicles are not palpable in the scrotum. Diagnosis depends on physical exam and ultrasound is performed only when other disorders are suspected. Treatment is dependent on patient age and testis position. In boys with persistent undescended testis by age 6 months, the condition is unlikely to spontaneously resolve. If the testis is palpable but not in the dependent intrascrotal location, an orchiopexy (bringing the testicle to the scrotum) is preferred. If the testis is non-palpable, a diagnostic laparoscopy is needed to inspect for an intra-abdominal testis, which requires a staged Fowler-Stephen’s orchiopexy.
Chlamydiae are obligate intracellular gram-negative bacteria. They lack a peptidoglycan layer and are best visualized using Giemsa stain. Chlamydiae species have a complex replication cycle consisting of 2 morphological forms: elementary bodies and reticulate bodies. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Sometimes, C. psittaci and C. pneumoniae are classified as a separate genus, Chlamydophila. C. trachomatis is the most common bacterium responsible for causing sexually transmitted diseases in the United States and is associated with urogenital infections, lymphogranuloma venereum, neonatal conjunctivitis, and trachoma. C. psittaci causes psittacosis (parrot fever), whereas C. pneumoniae causes atypical pneumonia.
Endometriosis is a common disease in which patients have endometrial tissue implanted outside of the uterus. Endometrial implants can occur anywhere in the pelvis, including the ovaries, the broad and uterosacral ligaments, the pelvic peritoneum, and the urinary and gastrointestinal tracts. Implants outside of the abdominopelvic cavity are also possible, though uncommon. Endometriosis typically presents in a reproductive-aged female with pelvic pain that worsens around menstruation. Endometrial implants tend to be inflammatory, leading to cyclic, chronic pain; adhesions; and an increased risk of infertility. The diagnosis is usually made clinically, though definitive diagnosis requires laparoscopy. Lab work is rarely useful. Management involves suppression of endometrial growth with progestins, typically with oral contraceptive pills. In severe cases, surgery is helpful to confirm the diagnosis and treat any implants.
Human immunodeficiency virus (HIV) infection is a sexually transmitted or blood-borne infection that destroys CD4 T cells. Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. These serious and life-threatening diseases are generally not seen in immunocompetent patients. Treatment of HIV is very important in managing these diseases, and the incidence of AIDS-defining conditions has declined with the use of antiretroviral therapy.
Human immunodeficiency virus (HIV), a single-stranded RNA virus belonging to the Retroviridae family, is the etiologic agent of acquired immunodeficiency syndrome (AIDS). The human immunodeficiency virus is a sexually transmitted or blood-borne infection that attacks CD4+ T lymphocyte cells, macrophages, and dendritic cells, leading to eventual immunodeficiency. The presentation is marked by constitutional symptoms such as lymphadenopathy and fever. Further progression predisposes to opportunistic infections and malignancies. Diagnosis is by enzyme immunoassay for HIV-1 and -2. Additional tests include HIV viral load, genotyping, and CD4+ T lymphocyte count to determine therapy and evaluate treatment response and disease progression. Immediate treatment with combination antiretroviral therapy is recommended.
Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Complications arise due to partial occlusion of vital branches off the aorta and reduced blood flow to the brain, visceral organs, and extremities. Patients often present with acute, tearing chest or back pain. Computed tomography is the diagnostic modality of choice. All type A dissections (ascending aorta) are a surgical emergency due to the risk of imminent rupture. Type B dissections (descending aorta) can be managed medically with impulse control using beta-blockers and calcium channel blockers. If there is evidence of malperfusion to visceral organs or extremities, aneurysm dilation to > 5 cm, retrograde extension into the ascending aorta, or intractable pain, the patient will need evaluation for endovascular or open repair.
Legg-Calvé-Perthes disease (LCPD) is characterized by idiopathic avascular necrosis of the femoral head. The disease presents as a limp with an insidious onset and associated hip pain. Legg-Calvé-Perthes disease primarily affects school-age children and has a male predominance. The exact mechanism of this disease is unknown and the diagnosis is made by clinical findings and imaging. Management can be conservative or surgical, depending on severity and the age of the patient.
Breast cancer is a disease characterized by malignant transformation of the epithelial cells of the breast. Breast cancer is the most common form of cancer and 2nd most common cause of cancer-related death among women. Genetic factors, age, and hormonal and environmental influence contribute to the progression of the disease. The most common histologic type is infiltrating ductal carcinoma, which is > 75% of all breast cancers. Screening mammography is recommended for early disease detection. Diagnosis is by core needle biopsy, with biologic factors determined by immunohistochemical testing. Surgery, systemic treatment (chemotherapy, biologic therapy, endocrine therapy), and radiation therapy (RT) are part of the early-stage and locally advanced disease management. In metastatic breast cancer, systemic treatment is utilized with palliative measures.
Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. M. tuberculosis are acid-fast, slowly growing bacteria that can survive in macrophages, allowing for a latent infection that can remain asymptomatic for decades, posing a challenge to diagnosis, therapy, and prevention. The diagnosis is established with tuberculin skin test, sputum culture, and lung imaging. The mainstay of management is anti-mycobacterial drugs.
The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Tolerating these forces is possible thanks to the bony alignment and substantial support from the static and dynamic stabilizers of the hip. Several muscle groups attach to the components of the hip joint, allowing for the joint's range of motion. The muscles that attach to the hip joint include those of the gluteal region and thigh.
Sjögren syndrome (SS) is an autoimmune, inflammatory condition where glandular tissues, such as the salivary and lacrimal glands, are infiltrated by lymphocytes, resulting in decreased tear and saliva production. The disease mainly affects middle-aged women, and is associated with other autoimmune conditions. Patients may experience symptoms and complications related to dry eyes and mouth. There is a wide range of extraglandular manifestations, including Raynaud's phenomenon, neuropathy, and cutaneous vasculitis. Patients are also at an increased risk of developing non-Hodgkin's lymphoma. Diagnosis is based on the presence of symptoms, and is validated by the clinical examination, serologic studies, or salivary gland biopsy. A multidisciplinary approach is needed to manage patients and targets symptomatic relief, with immunosuppressive therapy reserved for severe symptoms.
A lipoma is a benign neoplasm of fat cells (adipocytes) and the most common soft tissue tumor in adults. The etiology is unknown, but obesity is a predisposing factor; genetics also play a role, with multiple lipomas occurring in various inherited disorders. Lipomas can arise in any site with adipose tissue (including the gastrointestinal tract, chest cavity, retroperitoneum, and glands), but are most common in subcutaneous tissues of the trunk or proximal extremities. The treatment is not necessary for small asymptomatic lipomas. Surgical excision is the treatment if there is a cosmetic, functional, or diagnostic concern.
Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Certain populations may be more vulnerable to accidental hypothermia, including extremes of age, homeless, mentally ill, and alcohol and drug abusers. Evaluation should include assessment for associated trauma and contributing medical conditions. Management involves rewarming the patient by different methods based on the severity of the hypothermia.
Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Physical exam may reveal crepitus with joint motion and osteophyte formation (Heberden's and Bouchard's nodes). The diagnosis is clinical and supported with radiographic joint findings. Management includes conservative measures, analgesic medications, glucocorticoid intra-articular injections, and surgery for advanced disease.
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a disorder of impaired water excretion due to the inability to suppress the secretion of antidiuretic hormone (ADH). The inappropriate secretion of ADH can be due to various causes, including increased production by the pituitary gland due to trauma, disease, or certain medications; the ectopic secretion of ADH by cancer; or hereditary causes (nephrogenic SIADH). Syndrome of inappropriate antidiuretic hormone secretion is characterized by impaired water excretion leading to dilutional hyponatremia, which is mainly asymptomatic but may cause neurologic symptoms. Syndrome of inappropriate antidiuretic hormone secretion should be suspected in any patient with hyponatremia, hypo-osmolality, and high urine osmolality.
Foot deformities in children include congenital or acquired malformations of the feet. Two common examples are talipes equinovarus, commonly known as clubfoot, and metatarsus adductus, also called metatarsus varus. Depending on their etiology, foot deformities can be self-limiting or may require surgical correction. Early detection and recognition are crucial for proper treatment.
VACTERL association is a rare disorder that affects multiple body systems in fetal development. There is no clear genetic cause or inheritance pattern for the development of this disorder. The acronym VACTERL stands for the anomalies by which this condition is characterized: Vertebral abnormalities, Anal atresia, Cardiac defects, Tracheoesophageal abnormalities, Renal anomalies, and Limb abnormalities. Cognition is not affected. The diagnosis is one of exclusion in the setting of the presence of at least 3 of the above clinical features. Treatment is based on symptoms and abnormalities present.
CHARGE syndrome is a rare genetic condition with autosomal dominant inheritance in which almost all body systems are affected. The acronym CHARGE stands for the constellation of clinical features seen with this condition: Coloboma, Heart defects, Atresia choanae, Growth retardation, Genetic Abnormalities, and Ear abnormalities. Genetic testing confirms the diagnosis. Treatment is symptomatic with management of the airway, heart defects, and feeding ability as the priorities in early life. There is no definitive curative therapy.
Blount’s disease (BD) is an orthopedic childhood disorder characterized by outward bowing of the leg due to abnormal ossification of the medial aspect of the tibial epiphysis. Blount’s disease mostly affects children of African descent and tends to debut at approximately 1–3 years of age. Diagnosis is made by clinical findings and is confirmed by imaging. The goal of treatment is to correct the anatomy through bracing or surgical repair, according to the severity and age of the patient at diagnosis. The prognosis is excellent if treatment is promptly started.
Laryngomalacia and tracheomalacia are the most common upper airway conditions that produce stridor in newborns. Laryngomalacia and tracheomalacia tend to present in the 1st 2 weeks of life, with symptoms ranging from stridor to respiratory distress. The symptoms are caused by narrowing of the airway, which may be due to weakened cartilage, redundant tissue, external compression, or hypotonia of the affected area. Most cases are congenital, but tracheomalacia can be acquired in children or adults. Diagnosis is based on history, clinical findings, and confirmation by laryngoscopy or bronchoscopy. Treatment is supportive or surgical, depending on the severity. The majority of cases are self-limiting and resolve by 2–3 years of age, but some tracheomalacia cases can persist into adulthood.
Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. The timing and severity of presentation usually depend on the degree of right ventricular outflow obstruction. Definitive diagnosis is usually established by echocardiogram. Chest X-ray may show the classic boot-shaped heart. Definitive treatment involves surgical repair. Long-term prognosis is good for surgically corrected disease, but cardiovascular morbidity is common.
Williams syndrome (WS), also known as Williams-Beuren syndrome (WBS), is a genetic disease caused by a microdeletion on chromosome 7. Affected individuals have a characteristic elfin facies and short stature. Cognitive, developmental, and behavioral issues are common. Additionally, cardiovascular, connective tissue, endocrine, and renal anomalies may be present. Genetic testing confirms the diagnosis. Treatment is based on the clinical manifestations. Cardiovascular involvement needs to be followed closely because it is the main cause of mortality.
Abdominal injuries are classified according to their mechanism of injury as blunt or penetrating. In blunt abdominal trauma, the bowel, spleen, liver, kidneys, and pelvic organs can be injured. The extent and specific type of abdominal traumatic injury can be identified by a proper history and physical examination and confirmed by appropriate imaging studies. Management depends on the patient’s stability and specific type of injury.
Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. The majority of cases are mild, but presentation can vary from a mild concussion to a comatose state depending on the severity of the insult. Management ranges from observation to intensive care monitoring and neurosurgical interventions. Prognosis is good for mild injuries, but severe trauma can result in death or permanent damage.
Kallmann syndrome (KS), also called olfacto-genital syndrome, is a genetic condition that causes hypogonadotropic hypogonadism due to decreased secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus. Both sexes can be affected, although the incidence is much higher in males. The lack of sex hormones results in impaired pubertal development. Characteristically, there is an associated absence or decreased sense of smell (hyposmia or anosmia), which helps differentiate KS from other conditions. The diagnosis is made by hormone levels in blood and brain imaging showing the absence of olfactory structures. Genetic testing may assist in establishing a definite diagnosis. Treatment consists of hormone replacement therapy.
True hermaphroditism, or ovotesticular disorder of sexual development (ODSD), is characterized by the presence of an ovotesticular gonad that contains both ovarian and testicular elements. Individuals are usually born with ambiguous genitalia, but the diagnosis is rarely confirmed before puberty. The most common karyotype is 46,XX, and less often, 46,XY can be identified. Gonadal biopsy with histologic examination confirms the diagnosis. Management needs to consider the individual’s preferences wherever possible. Treatment options range from hormone replacement to surgical removal of part of the ovotestis gonad to improve fertility and to decrease the risk of malignancies.
Megacolon is a severe, abnormal dilatation of the colon, and is classified as acute or chronic. There are many etiologies of megacolon, including neuropathic and dysmotility conditions, severe infections, ischemia, and inflammatory bowel disease. Toxic megacolon is an acute form of megacolon with systemic toxicity, and carries the highest morbidity and mortality. Common symptoms include abdominal distention, pain, bloody diarrhea, or obstipation. Diagnosis depends on the underlying cause, and is usually established with a combination of the patient’s history, laboratory findings, and imaging studies. Patients with chronic megacolon may require laxatives, enemas, and bowel training. Management for acute megacolon includes supportive care, decompression, and potential surgery.
Paget's disease of bone (PDB), also known historically as osteitis deformans, is a focal disorder of bone metabolism that affects about 2%–9% of people. Commonly affected areas include the skull, spine, pelvis, and long bones of the lower extremity. The 2 main clinical manifestations of Paget's disease are bone pain and the consequences of bone deformities, such as fractures, osteoarthritis, or nerve impingement. The management includes bisphosphonates, calcitonin, and surgery for the management of fractures, deformities, and complications. The prognosis for PDB is good, especially if treatment is started before major changes have occurred in the bones.
Colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths in the United States. Colorectal cancer is a heterogeneous disease that arises from genetic and epigenetic abnormalities, with influence from environmental factors. Almost all cases of CRC are adenocarcinoma, and the majority of lesions come from the malignant transformation of an adenomatous polyp. Since most CRC cases are asymptomatic, screening colonoscopy or stool tests are generally recommended in patients ≥ 50 years of age. Along with screening, diagnosis is reached by colonoscopy, which allows visualization as well as tissue sampling. Treatment is primarily surgical, with chemotherapy reserved for advanced disease.
Barrett’s esophagus is a chronic gastroesophageal reflux disease (GERD) that leads to the replacement of stratified squamous epithelium with gastric columnar epithelium in the esophagus. The condition is associated with an increased risk of esophageal adenocarcinoma. Workup includes an esophagogastroduodenoscopy (EGD) showing proximal displacement of the squamocolumnar junction (Z-line) from the gastroesophageal junction (GEJ). Biopsies will confirm the diagnosis by revealing columnar epithelium and goblet cells in the distal esophagus. Treatment is primarily with proton pump inhibitors (PPIs) and lifestyle modifications. Surveillance with repeated EGD and biopsy is necessary to monitor for early signs of dysplasia.
Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). This condition may eventually lead to inflammation (esophagitis), metaplasia (Barrett’s esophagus), and progression to esophageal cancer. Uncomplicated GERD can be managed with lifestyle changes and over-the-counter medications. Sometimes, however, stronger medications or surgery may be required to ease symptoms and prevent complications.
Osteogenesis imperfecta (OI), or “brittle bone disease,” is a rare genetic connective tissue disorder characterized by severe bone fragility. Although OI is considered a single disease, OI includes over 16 genotypes and clinical phenotypes with differing symptom severity. Of these 16, types I–IV are the most common. Because of the rarity of OI, OI is considered an “orphan disease” in the United States. Diagnosis is made clinically, through history and examination, and is confirmed by radiologic findings and DNA analysis. While there is no definitive cure, treatment is supportive, usually involving bisphosphonates, and is focused on reducing pain, reducing fracture frequency, reducing bony deformity, and increasing ambulation. The prognosis is variable, depending on the OI type.
Prostate cancer is one of the most common cancers affecting men. In the United States, the lifetime risk of being diagnosed with prostate cancer is around 11%, and the lifetime risk of dying from this condition is 2.5%. Prostate cancer is a slow-growing cancer that takes years (even decades) to develop into advanced disease, and many men remain asymptomatic and die from other medical conditions.
Cardiopulmonary resuscitation (CPR) is an emergency procedure used in patients with cardiac arrest. Cardiopulmonary resuscitation combines the use of chest compressions, artificial ventilation, and, when available, an automatic external defibrillator (AED) to maintain circulatory flow and oxygenation to vital structures. Cardiopulmonary resuscitation is an integral part of basic life support (BLS) and advanced cardiovascular life support (ACLS). High-quality CPR improves the likelihood of survival. Some patients in critical situations request a do not resuscitate (DNR) order, which instructs health care providers not to do CPR if a patient suffers cardiac arrest.
A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Symptom severity depends on the degree of the collapsed lung. A large or tension pneumothorax can result in cardiopulmonary collapse. A diagnosis is made with imaging, though tension pneumothorax is a clinical diagnosis. Management is based on the size and stability of the patient, and can include needle decompression and chest tube (thoracostomy) placement.
Esophagitis is the inflammation or irritation of the esophagus. The major types of esophagitis are medication-induced, infectious, eosinophilic, corrosive, and acid reflux. Patients typically present with odynophagia, dysphagia, and retrosternal chest pain. Diagnosis is by endoscopy and biopsy. Laboratory tests and imaging are obtained, depending on the degree of damage and involvement of other organ systems. Treatment for esophagitis depends on the underlying etiology and includes dietary changes, avoidance of offending agents, antibiotic therapy, or proton pump inhibitor use. In severe cases such as in corrosive injury, surgery may need to be performed. If left untreated, esophagitis can lead to complications such as strictures, metaplasia of the esophagus, and development of malignancy.
The catabolism of amino acids results in the release of nitrogen in the form of ammonium. This excess nitrogen is transported to the liver and kidneys and eliminated from the body in the form of urea via the urine. The urea cycle (or ornithine cycle) takes place mainly in the liver and comprises the synthesis of urea from ammonium, CO2, aspartate, and bicarbonate. The cycle involves 1 feeder reaction to incorporate the ammonium and 4 reactions in the cycle. It prevents cytotoxic hyperammonemia levels.
Hyperprolactinemia is defined as a condition of elevated levels of prolactin (PRL) hormone in the blood. The PRL hormone is secreted by the anterior pituitary gland and is responsible for breast development and lactation. Many factors contribute to the development of hyperprolactinemia. The most common cause is PRL-secreting pituitary adenomas (prolactinomas). Diagnosis is achieved through hormonal testing to rule out other endocrine conditions and confirmatory imaging tests. Dopamine agonists are the 1st-line drugs for treatment. Refractory cases require surgery and possibly radiation therapy.
Fragile X syndrome (FXS), also known as Martin-Bell syndrome, is a genetic condition with X-linked inheritance. Both boys and girls may be affected, but the severity is much worse in boys. Characteristic features include a long face, prominent forehead and chin, large ears, flat feet, and large testes post-puberty for boys. Fragile X syndrome is the most common cause of inherited intellectual disability and is also associated with autism. Genetic testing confirms the diagnosis. Treatment is aimed at improving associated symptoms.
Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (commonly known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Neurologic, cardiac, ocular, and joint manifestations are also common in later stages. Diagnosis relies on clinical findings and tick exposure, and is supported by serological testing. Antibiotics are used for treatment. Avoidance of tick exposure is key to prevention in endemic areas.
Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. The skin, lungs, and central nervous system are also affected. Patients are usually tall with long limbs, fingers, and toes, and hypermobile joints. Associated conditions include aortic aneurysm or dissection, mitral valve prolapse, and lens dislocation. Diagnosis is made clinically with set criteria, and genetic testing is done only when it may affect the management. Medical or surgical management is based on clinical manifestations. Cardiovascular involvement is followed closely, as it is the main cause of mortality.
Primary sclerosing cholangitis (PSC) is an inflammatory disease that causes fibrosis and strictures of the bile ducts. The exact etiology is unknown, but there is a strong association with inflammatory bowel disease (IBD). Patients typically present with an insidious onset of fatigue, pruritus, and jaundice, which can progress to cirrhosis and complications related to biliary obstruction. The diagnosis is established with magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP). Liver transplantation is the only definitive treatment and is indicated in patients with advanced liver disease.
Diverticula are protrusions of the bowel wall occurring most commonly in the colon. The condition of having diverticula (called diverticulosis) is mostly asymptomatic. These diverticula can become symptomatic, however, when associated with diseases. Diverticulitis is the inflammation of diverticula, often presenting with lower abdominal pain and changes in bowel habits. The condition may be further complicated by abscess, perforation, fistula, and bowel obstruction. Management consists of antibiotics, fluid resuscitation, and bowel rest. Surgery is required for complications, failure of medical management, and recurrent disease. In most cases of diverticular bleeding, spontaneous cessation occurs. Invasive intervention will be needed for persistent or recurrent bleeding.
Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Onset may be insidious (atherosclerosis) or abrupt (thrombosis). Diagnosis is made with the clinical history, exam, and measurement of the ankle-brachial index. Imaging studies can determine the location and extent of the arterial disease. Treatment varies depending on the severity but can include lifestyle modifications, antiplatelet therapy, risk factor modifications, phosphodiesterase inhibitors, and revascularization.
Ectopic pregnancy refers to the implantation of a fertilized egg (embryo) outside the uterine cavity. The main cause is disruption of the normal anatomy of the fallopian tube. Consequently, affected patients may suffer from acute abdominal pain as the developing embryo increases in size. Ectopic pregnancy can be quickly diagnosed by means of an ultrasound and laboratory analysis. Management can be expectant, medical, or surgical. Severe cases involving rupture of the fallopian tube and hemorrhage are considered a medical emergency and require immediate surgery.
Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. The diagnosis can frequently be established clinically, but imaging is used in uncertain cases. Computed tomography (CT) scan provides the highest diagnostic accuracy. Perforation occurs in 13%–20% of cases and can present as localized (abscess/phlegmon) or free perforation with generalized peritonitis. The standard treatment is appendectomy, but localized perforations are frequently managed non-operatively with antibiotics.
Drug-induced liver injury (DILI) is the most common cause of acute liver failure (ALF). Hepatotoxic drugs can cause injury to the hepatocytes directly in a predictable dose-dependent way or through idiosyncratic reactions (which may be mediated by immune or non-immune processes). The injury mechanisms can have the following effects: hepatitis, cholestasis, vascular lesions, or overlapping changes. The presentation can be acute or chronic, with severe toxicity manifesting as fulminant liver failure. The diagnosis of DILI requires a thorough history and laboratory tests including liver function tests (LFTs) and drug levels, if available. Management consists of discontinuing the drug, supportive therapy, and monitoring for complications. Acetaminophen, 1 of the most common causes of DILI, has a specific treatment, N-acetylcysteine (NAC).
Scarlet fever is a clinical syndrome consisting of streptococcal pharyngitis accompanied by fever and a characteristic rash caused by pyrogenic exotoxins. Scarlet fever is a non-suppurative complication of streptococcal infection that is more commonly seen in children. Incidence peaks during the winter and spring in temperate climates. The rash begins in the 1st 24–48 hours of illness. Starting in the face or neck, the exanthem spreads to the trunk and extremities but spares the palms and soles. With the infection, the face looks flushed, accompanied by circumoral pallor and a strawberry tongue (enlarged papillae). The minute papules feel like sandpaper. Diagnosis is usually made clinically, confirmed with a rapid antigen detection test (RADT) or throat culture. Treatment is with penicillin or amoxicillin.
Supraventricular tachycardias are related disorders in which the elevation in heart rate is driven by pathophysiology in the atria. This group falls under the larger umbrella of tachyarrhythmias and includes paroxysmal supraventricular tachycardias (PSVTs), ventricular pre-excitation syndromes (i.e. Wolff-Parkinson-White syndrome), atrial flutter, multifocal atrial tachycardia, and atrial fibrillation. Sinus tachycardia (> 100/min) is not a pathologic arrhythmia. The diagnosis of these conditions can be made using electrocardiogram (ECG), and treatment differs depending on the condition.
Pneumoconiosis is an occupational disease that results from the inhalation and deposition of mineral dusts and other inorganic particles in the lung. It can be categorized according to the type of causative particle involved or by the type of response provoked. Coal, silica, asbestos, and talc are the classic fibrogenic types, while beryllium provokes a granulomatous response, and cobalt is associated with giant cell pneumonia. Iron, tin, and barium are considered benign or inert particle types because they do not cause the same type of reactions as the others.
After exposure to the fibrogenic types of particles, macrophages and fibroblasts become activated within the pulmonary parenchyma leading to chronic inflammation and fibrosis, which can progress to respiratory failure and death. Occupational history and chest X-rays are the mainstays of diagnosis and staging. Management is mainly symptomatic.
Nevi (singular nevus), also known as “moles,” are benign neoplasms of the skin. Nevus is a non-specific medical term because it encompasses both congenital and acquired lesions, hyper- and hypopigmented lesions, and raised or flat lesions. Additionally, nevi can be found within different depths of the layers of the skin and originate from various types of cells (e.g., melanocytic, connective tissue, vascular). Nevi also have a wide variety of characteristic forms, which must be well understood in order to differentiate nevi from malignant melanoma. In this concept page, we will cover the basic classifications and most common types of nevi as well as the clinical criteria used to assess them.
Craniosynostosis is the premature fusion of 1 or more cranial sutures during the 1st year of life. Craniosynostosis is classified as simple or complex, and can be caused by environmental factors or genetic syndromes. Patients are typically asymptomatic and concern may arise from caregiver observations. Diagnosis is made clinically and by imaging of the head. Treatment is surgical and prognosis depends on classification and the presence of genetic syndromes.
Esophageal atresia is a congenital anomaly in which the upper esophagus is separated from the lower esophagus and ends in a blind pouch. The condition may be isolated or associated with tracheoesophageal fistula, which is an abnormal connection between the trachea and esophagus. The most common congenital tracheoesophageal abnormality is a combination of esophageal atresia and distal tracheoesophageal fistula. The defect manifests early after birth as an inability to feed, regurgitation, choking, and aspiration, and requires surgical correction. Survival is good, but long-term complications are common.
Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) are serious, acute complications of diabetes mellitus. Diabetic ketoacidosis is characterized by hyperglycemia and ketoacidosis due to an absolute insulin deficiency. Hyperosmolar hyperglycemic state occurs due to a relative deficiency of insulin or insulin resistance, leading to severe hyperglycemia and elevated serum osmolality. Triggering factors include inadequate insulin therapy, underlying infection, concurrent medical illness, or drug side effects. Diabetic ketoacidosis patients tend to be younger, with type 1 diabetes, who present with acute symptoms, including abdominal pain, nausea, and vomiting. On the other hand, HHS patients are generally older, with type 2 diabetes, and will have gradual onset of symptoms, including altered mental status and neurologic changes. Both sets of patients will have polyuria, polydipsia, and evidence of severe dehydration. Diagnosis is based on laboratory values demonstrating hyperglycemia with ketoacidosis or hyperosmolality. Management involves aggressive fluid rehydration, insulin therapy, and correction of electrolyte abnormalities.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a type of intravascular hemolytic anemia. The condition is inherited in an X-linked recessive manner. Patients have episodic hemolysis due to an oxidative stressor that causes damage to red blood cells, which lack sufficient NADPH to protect them from oxidative injury.
Constipation is a common complaint in children that is relatively defined for individual age groups based on the frequency and difficulty of defecation and stool consistency. The majority of constipation cases are functional or non-organic. Clinical presentation may vary, from insufficient evacuation noted by the parents, to complaints of abdominal pain, to secondary incontinence. Often, a combination of non-pharmacologic and pharmacologic management is needed for evacuating bowel content, eliminating pain upon defecation, and improving bowel habits.
Asthma is a chronic inflammatory condition of the small airways of the lungs. The condition is characterized by airway hyperresponsiveness, variable airway obstruction, and airway inflammation. Manifestations include episodic wheezing, coughing, and shortness of breath. Management of asthma aims to reduce symptoms and minimize future risks and adverse outcomes (hospitalizations, loss of lung function, etc.). Medications commonly utilized include inhalers that allow bronchodilation and inflammatory control. Biologic agents are available for severe asthma.
Congenital duodenal obstructions are a group of inborn conditions that cause obstruction of the lumen of the duodenal segment of the small intestine, impeding the passage of food and gastric juices. The condition may have intrinsic etiologies, such as duodenal atresia (most common) and/or extrinsic etiologies, such as an annular pancreas. The hallmark of duodenal obstruction is bilious vomiting. The condition can be diagnosed through prenatal or postnatal ultrasound. Associated anomalies, including congenital heart disease, are common. Treatment includes fluid resuscitation and surgical duodenoduodenostomy.
Hereditary hemochromatosis (HH) is an autosomal recessive disorder most often associated with HFE gene mutations. Patients have increased iron intestinal absorption and iron deposition in several organs, such as the liver, heart, skin, and pancreas. The clinical presentation includes the triad of cirrhosis, diabetes, and skin bronzing. Other findings depend on the organ(s) involved. Diagnosis consists of iron studies, showing transferrin (Tf) and ferritin elevation. Genetic screening is recommended among family members. Imaging and invasive studies are performed depending on the associated complications. Management requires phlebotomy (or iron chelation therapy in some cases) to prevent disease progression. The prognosis is good for patients who are early in the disease and undergoing treatment. The presence of hepatic fibrosis is a poor prognostic factor.
Peptic ulcer disease (PUD) refers to the full-thickness ulcerations of duodenal or gastric mucosa. The ulcerations form when exposure to acid and digestive enzymes overcomes mucosal defense mechanisms. The most common etiologies include Helicobacter pylori (H. pylori) infection and prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs). Patients may be asymptomatic or may present with abdominal pain, nausea, and early satiety. Peptic ulcer disease typically responds well to medical treatment consisting of H. pylori eradication, eliminating risk factors, and proton pump inhibitors (PPIs). If left untreated, it can lead to bleeding, perforation, gastric outlet obstruction, and gastric cancer.
Gastritis refers to inflammation of the gastric mucosa. Gastritis may occur suddenly (acute gastritis) or slowly over time (chronic gastritis). Gastritis may be asymptomatic or with symptoms, including burning abdominal pain (which either worsens or improves with eating), dyspepsia, nausea, and vomiting. The most common etiologies for gastritis are Helicobacter pylori infection and autoimmune disease. Chronic gastritis is a risk factor for gastric cancer. Management involves the use of proton pump inhibitors with antibiotics (in case of H. pylori infection), avoidance of offending agents, and replacement of associated deficiencies.
Mitral valve prolapse (MVP) is the most common cardiac valvular defect, and is characterized by bulging of the mitral valve (MV) cusps into the left atrium (LA) during systole. Mitral valve prolapse is most commonly due to idiopathic myxomatous degeneration. Patients are typically asymptomatic. Auscultation generally reveals a mid-to-late systolic click, followed by a possible regurgitation murmur. The diagnosis is confirmed by an echocardiogram. Treatment is generally not required for asymptomatic patients.
Mitral stenosis (MS) is the narrowing of the mitral valve (MV) orifice, leading to obstructed blood flow from the left atrium (LA) to the left ventricle (LV). Mitral stenosis is most commonly due to rheumatic heart disease. Mitral stenosis leads to impaired LV diastolic filling, increased LA pressure, and LA dilation, which can result in atrial fibrillation, pulmonary congestion, pulmonary hypertension, and right heart failure. Symptoms include exertional dyspnea, orthopnea, palpitations, fatigue, and hoarseness. Physical examination will demonstrate an opening snap, followed by a rumbling diastolic murmur. An echocardiogram is used for diagnosis. Treatment includes sodium restriction, diuretics, atrial fibrillation management, possible anticoagulation, and percutaneous commissurotomy or surgery.
Mitral regurgitation (MR) is the backflow of blood from the left ventricle (LV) to the left atrium (LA) during systole. Mitral regurgitation may be acute (myocardial infarction) or chronic (myxomatous degeneration). Acute and decompensated chronic MR can lead to pulmonary venous congestion, resulting in symptoms of dyspnea, orthopnea, and fatigue. Acute MR is an emergency because it can cause cardiogenic shock, and requires medical stabilization and surgery. In chronic severe MR, patients are evaluated for surgical repair or replacement.
The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. The boundaries are formed by various muscles of the thigh and leg.
The airway, breathing, and circulation, disability and exposure (ABCDE) assessment is the mainstay management approach used in managing critically ill patients. The ABCDEs are the essential 1st steps to perform in many situations including unresponsive patients, cardiac arrests, and critical medical or trauma patients. For the trauma patient, ABCDE is included in the primary survey, the initial evaluation, and management of injuries.
Drowning occurs due to respiratory impairment from submersion or immersion in a liquid medium. Aspiration of water leads to hypoxemia, which affects all organ systems, resulting in respiratory insufficiency and acute respiratory distress syndrome (ARDS), cardiac arrhythmias, and neuronal damage. The management of drowning focuses initially on ventilatory support followed by cardiopulmonary resuscitation. As drowning is most often preventable, prevention is the focus of most interventions.
Transfusion-related complications occur during or after a blood product is given. These complications can be classified as immunologic, non-immunologic and acute, and delayed. Non-immunologic reactions are caused by the transmission of disease in blood products, and immunologic reactions are antigen-antibody–mediated. Symptoms can range from mild itching, chills, and urticaria (hives) to high fever, severe shortness of breath, jaundice, hypotension, or hemoglobinuria. Severe reactions can lead to death.
Cholecystitis is the inflammation of the gallbladder (GB) usually caused by the obstruction of the cystic duct (acute cholecystitis). Mechanical irritation by gallstones can also produce chronic GB inflammation. Cholecystitis is one of the most common complications of cholelithiasis (calculous cholecystitis) but inflammation without gallstones (acalculous cholecystitis) can occur in a minority of patients. The acute type usually presents with right upper quadrant (RUQ) pain, fever, and leukocytosis. The diagnosis is made clinically and confirmed via ultrasound (US). The definitive management is cholecystectomy, preferred to be performed within 72 hours. This condition can present as a mild condition or as a severe disease (with complications such as gallbladder gangrene, perforation, empyema) which require emergent intervention.
Children are particularly vulnerable to developing dehydration because they have higher insensible water loss and more elevated metabolic rates than adults. In addition, children's inability to communicate their needs compounds with large losses of fluids (e.g., diarrhea, vomiting), putting them at even higher risk. Dehydration is defined as a decrease in total body water, and can be characterized as mild, moderate, or severe. Fluid replacement treatment is based on severity. Clinicians must be prepared to administer optimal rehydration therapy in addition to the other required measures for the causal illness. When treated promptly, dehydration starts to resolve clinically within the first few hours.
Hemolytic uremic syndrome (HUS) is a clinical phenomenon most commonly seen in children that consists of a classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Hemolytic uremic syndrome is a major cause of acute kidney injury in children and is most commonly associated with a prodrome of diarrheal illness caused by Shiga-like toxin-producing bacteria. Laboratory analysis confirms microangiopathic hemolytic anemia (hemoglobin < 8 g/dL, schistocytes, and negative direct Coombs), thrombocytopenia (platelet count < 140,000/mm³), and acute kidney injury (elevated creatinine and blood urea nitrogen (BUN)). The management of HUS is primarily through supportive care.
Asthma is a chronic inflammatory condition causing intermittent airway obstruction, wheezing, cough, and dyspnea. Genetics and environmental factors play a significant role in etiology. A diagnosis of asthma in children often involves careful history taking, physical examination, pulmonary function tests, and radiologic studies to rule out other conditions. The goal is to minimize symptoms, exacerbations, and functional as well as psychological morbidity. Treatment also involves relief and chronic pharmacotherapy.
Acute bronchiolitis is a respiratory condition caused by inflammation of the bronchioles. The condition is a common cause of hospitalization in children in the United States, with the majority of cases caused by respiratory syncytial virus (RSV). Patients usually present with upper respiratory symptoms, such as cough and congestion, and later develop lower respiratory signs, including dyspnea, wheezing, crackles, and hypoxia, for up to 10 days. Diagnosis is clinical and treatment is directed at improving oxygenation and hydration. As the disease course is self-limiting, acute bronchiolitis has good prognosis with appropriate management.
A neonate, or newborn, is defined as a child less than 28 days old. A thorough physical examination should be performed within the first 24 hours of life to identify abnormalities and improve outcomes by offering timely treatment. Physical examination of the newborn is typically performed sequentially from head to toe, keeping in mind common neonatal pathologies based on family and prenatal history, risk factors, and geographic region.
A peritonsillar abscess (PTA), also called quinsy, is a collection of pus between the capsule of the palatine tonsil and the pharyngeal muscles. A PTA is usually a complication of acute tonsillitis, an infection caused by group A Streptococci. Patients often present with a sore throat, trismus, and a muffled voice. The infection responds well to drainage and antibiotics. Complications such as the extension of infection to deeper spaces are possible.
Urinary tract infections (UTIs) are commonly seen in children. Urinary tract infections may present as cystitis, pyelonephritis, or asymptomatic bacteriuria, and their clinical presentation may vary widely depending on the age of the patient. Fecal E. coli is the most common pathogen. Routes of infection may be ascending (most common) or hematogenous. Urinary tract infection is suspected based on lower UTI symptoms (dysuria, frequency) or upper UTI symptoms (fever) and positive urinalysis findings. Urine culture confirms the diagnosis. Most cases respond to oral antibiotics. Further investigation through imaging and, at times, hospital admission is required in refractory or recurrent cases.
Infectious mononucleosis (IM), also known as “the kissing disease,” is a highly contagious viral infection caused by the Epstein-Barr virus. Its common name is derived from its main method of transmission: the spread of infected saliva via kissing. Clinical manifestations of IM include fever, tonsillar pharyngitis, and lymphadenopathy. Diagnosis is clinical and confirmed through heterophile antibody testing or specific serologic antibody testing. There is currently no specific antiviral therapy available for this condition.
Cholelithiasis (gallstones) is the presence of stones in the gallbladder. Most gallstones are cholesterol stones, while the rest are composed of bilirubin (pigment stones) and other mixed components. Patients are commonly asymptomatic but may present with biliary colic (intermittent pain in the right upper quadrant). The diagnosis is established by ultrasound. Management options include supportive care to prevent and control associated symptoms. When indicated, cholecystectomy is the definitive treatment. Gallstones may lead to complications such as choledocholithiasis (a stone trapped in the common bile duct), cholecystitis (inflammation of the gallbladder), or cholangitis (biliary sepsis). These conditions require urgent medical attention.
Hepatic encephalopathy is a reversible condition in which elevated ammonia levels cause impaired brain function in patients with advanced liver disease. Hepatic encephalopathy can be precipitated by conditions that affect the normal absorption, metabolism, or clearance of ammonia, including dehydration, renal failure, infections, and gastrointestinal bleeding. Patients present with a progression of symptoms, from minimal confusion and asterixis to stupor and coma. Diagnosis is clinical and requires the exclusion of alternative diagnoses. Management involves addressing the causative factor and decreasing the systemic absorption of ammonia with lactulose or rifaximin.
Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of HRS is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Patients typically present with edema, oliguria or anuria, and ascites in the setting of acute or chronic liver injury. Hepatorenal syndrome is considered a diagnosis of exclusion. Treatment is with agents that cause systemic vasoconstriction and, therefore, improve renal perfusion. This includes octreotide and midodrine. Most cases of hepatorenal syndrome have a poor prognosis.
The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. The apex houses various vessels and nerves, including the axillary artery and its branches, the axillary vein and its tributaries, the branches of the brachial plexus, and the axillary lymph nodes.
Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable bowel syndrome is a diagnosis of exclusion, and organic causes should be ruled out. Once diagnosed, the emphasis is on education and reassurance. Dietary modifications and symptom-control measures may also be instituted.
Thromboangiitis obliterans (TAO), also known as Buerger’s disease, is a rare condition causing inflammatory thrombosis of the small- to medium-sized arteries and veins of the upper and lower extremities. Patients are typically young smokers presenting with distal extremity ischemia, ulcers, or gangrene. Superficial thrombophlebitis and Raynaud's phenomenon can be early manifestations. Diagnosis is based on clinical findings, vascular testing, and angiography. Other potential diagnoses must be ruled out. The use of tobacco products is strongly associated with the disease; therefore, smoking cessation is an essential part of management and decreases the risk of amputation.
Calcium channel blockers (CCBs) are a class of medications that inhibit voltage-dependent L-type calcium channels of cardiac and vascular smooth muscle cells. The inhibition of these channels produces vasodilation and myocardial depression. There are 2 major classes of CCBs: dihydropyridines and non-dihydropyridines, which differ in their selectivity for cardiac or vascular smooth muscle cells. Broadly, these agents are used to treat hypertension, angina, and tachyarrhythmias. Side effects are from vasodilation (headache, peripheral edema, reflex tachycardia) or a consequence of reduced myocardial contractility and nodal conduction velocity (bradycardia).
Gastrointestinal bleeding (GIB) is a symptom of multiple diseases within the gastrointestinal (GI) tract. Gastrointestinal bleeding is designated as upper or lower based on the etiology’s location to the ligament of Treitz. It is more common to have bleeding in the upper GI tract, with peptic ulcer disease being the most frequent cause. Depending on the location of the bleeding, the patient may present with hematemesis (vomiting blood), melena (black, tarry stool), or hematochezia (fresh blood in stools). Some patients presenting with GIB can be hemodynamically unstable and require emergent stabilization and evaluation. The source of the bleed can often be located and treated with endoscopy.
Ribonucleic acid (RNA), like deoxyribonucleic acid (DNA), is a polymer of nucleotides that is essential to cellular protein synthesis. Unlike DNA, RNA is a single-stranded structure containing the sugar moiety ribose (instead of deoxyribose) and the base uracil (instead of thymine). While DNA stores the genetic information, RNA generally carries out the instructions encoded in the DNA but RNA also executes diverse non-coding functions. There are 3 major types of RNA that perform different but collaborative roles in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). During transcription, RNA is synthesized from DNA through a series of steps catalyzed by the enzyme RNA polymerase. The mRNA formed will serve as an amino acid template for protein synthesis. Translation proceeds with the tRNA transporting the corresponding amino acid based on the deciphered nucleotide sequence (codon) in the mRNA. The ribosomes, which are composed of rRNA, then facilitate the assembly of amino acids into a polypeptide. These components work together to convert the mRNA template obtained from DNA into the desired protein.
Celiac disease (also known as celiac sprue or gluten enteropathy) is an autoimmune reaction to gliadin, which is a component of gluten. Celiac disease is closely associated with HLA-DQ2 and HLA-DQ8. The immune response is localized to the proximal small intestine and causes the characteristic histologic findings of villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis. Patients typically present with diarrhea and symptoms related to malabsorption (steatorrhea, weight loss, and nutritional deficiencies). Patients are screened with serological antibody testing, and diagnosis is confirmed by small intestine biopsy. Treatment requires a lifelong gluten-free diet.
Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychologic exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). The medical history and physical exam of a patient presenting with dyspnea should be used to rule out certain conditions or suggest the most likely cause of the respiratory discomfort. Management focuses on treating the underlying condition.
Wheezing is an abnormal breath sound characterized by a whistling noise that can be relatively high-pitched and shrill (more common) or coarse. Wheezing is characterized by a whistling noise produced by the movement of air through narrowed or compressed small (intrathoracic) airways. Wheezes can be inspiratory or (more commonly) expiratory. Since wheezing is experienced by the patient and witnessed by the physician, the condition is a symptom as well as a physical finding. Respiratory diseases that result in obstruction usually lead to wheezing, most commonly asthma; however, other causes also exist, including allergies, pneumonia, and heart failure, among others.
Atrial flutter is a regular supraventricular tachycardia characterized by an atrial heart rate between 240/min and 340/min (typically 300/min), atrioventricular (AV) node conduction block, and a “sawtooth” pattern on an electrocardiogram (ECG). There are many cardiac and non-cardiac causes, but patients will usually have underlying structural heart disease. Symptoms include palpitations, shortness of breath, chest pain, dizziness, and nausea. Management is similar to atrial fibrillation, with a focus on rhythm control and preventing systemic embolization.
Bradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea. Bradyarrhythmia is due to dysfunction in the sinoatrial (SA) node, atrioventricular (AV) node, or the lower conduction system. Bradyarrhythmia can be associated with an intrinsic cardiac abnormality or with medications, electrolyte imbalances, and systemic diseases. Arrhythmia is detected by electrocardiogram (ECG). Additional tests such as event recorders are performed if symptoms are less frequent and require a longer observation period. There are bradyarrhythmias requiring no intervention. In symptomatic or life-threatening conduction abnormalities such as complete heart block, permanent pacemaker placement is the mainstay of treatment.
Aortic stenosis (AS), or the narrowing of the aortic valve aperture, is the most common valvular heart disease. While rheumatic heart disease remains the most frequent etiology worldwide, degenerative AS and congenital bicuspid valve defect are the 2 usual causes in developed countries. Aortic stenosis gradually progresses to heart failure, producing exertional dyspnea, angina, and/or syncope. A crescendo-decrescendo systolic murmur is audible in the right upper sternal border. Doppler echocardiography is the imaging of choice, showing structural and flow changes in the valvular area. Valve replacement is the only effective treatment for symptomatic severe AS. Indications for the procedure depend on the patient's symptoms, degree of AS severity, exercise tolerance, concurrent cardiac abnormalities, surgical risk, and life expectancy.
Gastric cancer is the 3rd-most common cause of cancer-related deaths worldwide. The majority of cases are from adenocarcinoma. The modifiable risk factors include Helicobacter pylori infection, smoking, and nitrate-rich diets. Hereditary syndromes, pernicious anemia, and prior partial gastrectomy are among the endogenous risk factors. When symptoms such as epigastric fullness, vomiting, and weight loss occur, it is likely that the cancer is in the advanced stage. Diagnosis is confirmed with esophagogastroduodenoscopy and biopsy. Imaging studies and laparoscopy aid in determining the cancer stage. Consequently, staging dictates the management approach. Management consists of gastrectomy and chemoradiotherapy. Most cases are diagnosed in late stages, indicating a generally poor prognosis.
Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Acute valvular insufficiency, which rapidly progresses to cardiogenic shock, is an emergency requiring immediate aortic valve surgery. Chronic AR develops gradually, allowing the left ventricle to adapt to the increased stroke volume. Thus, echocardiogram shows left ventricular hypertrophy and dilation along with valvular abnormalities. Eventually, congestive heart failure occurs as the left ventricle is unable to handle the hemodynamic overload. Aortic valve replacement is the mainstay of treatment for AR with left ventricular dysfunction.
Glycolysis is a central metabolic pathway responsible for the breakdown of glucose and plays a vital role in generating free energy for the cell and metabolites for further oxidative degradation. Glucose primarily becomes available in the blood as a result of glycogen breakdown or from its synthesis from noncarbohydrate precursors (gluconeogenesis) and is imported into cells by specific transport proteins. Glycolysis occurs in the cytoplasm and consists of 10 reactions, the net result of which is the conversion of 1 C6 glucose to 2 C3 pyruvate molecules. The free energy of this process is harvested to produce adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide hydride (NADH), key energy-yielding metabolites. The overall stoichiometry of the pathway is: glucose + 2 Pi + 2 ADP + 2 NAD+ > 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O (H+: hydrogen ion, Pi: phosphate ion, NAD+: nicotinamide adenine dinucleotide).
Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Diagnosis is confirmed with a pulmonary function test showing a reversible obstructive pattern. Treatment, based on symptom severity, includes bronchodilators and inhaled corticosteroids for control of inflammation. Biologic agents targeting inflammatory mediators have been developed for severe persistent asthma.
The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. The muscles are grouped into 2 compartments: anterior and posterior. The function of these muscles is flexion and extension of the wrist and fingers, while also contributing to flexion of the elbow.
Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks' gestation. Omphalocele is frequently associated with genetic syndromes and chromosomal abnormalities. Prenatal diagnosis can be made by prenatal ultrasound, maternal blood elevated ⍺-fetoprotein, and fetal chromosomal analysis. Treatment includes immediate hemodynamic stabilization followed by primary or staged surgical repair.
Gastroschisis is a congenital abdominal wall defect characterized by the complete lack of closure of the abdominal musculature. A portion of intestine does not return to the abdominal cavity, thereby remaining in its early embryonic herniated state but with no coverings. Diagnosis is made by prenatal ultrasonography. Findings include a paraumbilical wall defect with uncovered herniated intestines. Fetal surveillance and bowel monitoring are done to measure fetal growth and amniotic fluid volume, as well as observe any bowel changes. The mode and timing of delivery depend on these factors. Neonatal care includes protection of the exposed bowel, fluid resuscitation, and airway maintenance. Primary closure can be performed within hours of birth. The presence of a large gastroschisis or thickened and dilated bowel warrants delayed closure, with the use a bowel covering or “silo,” and serial bowel reduction.
Retinopathy of prematurity (ROP) is a condition seen in premature infants of low birth weight that is characterized by progressive and excessive neovascularization. The condition is caused by the formation of blood vessels and fibrovascular tissue behind the lens (hence the former use of the term “retrolental fibroplasia”). Infants affected by ROP develop severe visual impairment or can become blind. Treatment with laser photocoagulation prevents vision loss in 95% of cases.
The entire DNA of a cell is replicated during the S (synthesis) phase of the cell cycle. The principle of replication is based on complementary nucleotide base pairing: adenine forms hydrogen bonds with thymine (or uracil in RNA) and guanine forms hydrogen bonds with cytosine. Replication occurs prior to cell division in the S phase of the cell cycle in order to allow 2 sets of chromosomes to be present during the metaphase of mitosis, after which they are equally partitioned into 2 new cells during separation (anaphase).
Hand and wrist pain is very common among the general population. Up to 30% of adults will have hand pain during their lives, and half of all cases progress to chronic pain. The causes of hand and wrist pain can be classified into mechanical (e.g., fractures, inflammation, ligament tear), neurologic (e.g., nerve entrapment), and systemic (e.g., autoimmune arthritis). Reaching an accurate diagnosis involves following an evidence-based systematic approach. Treatment includes reducing stress on the ligaments, pain management, and surgery.
Sudden infant death syndrome (SIDS) describes the sudden death of an otherwise healthy infant (< 1 year of age) with no identifiable cause. Sudden infant death syndrome is the leading cause of death in children between 1 and 12 months of age in the United States. Sudden infant death syndrome is a diagnosis of exclusion and can only be confirmed after other causes of death have been ruled out with a thorough medical history and autopsy. Providing parents with preventative education is key to reducing the risk of SIDS. Preventative measures include having infants sleep supine, on firm surfaces, with no clutter in their crib.
Schizophrenia is a chronic mental health disorder characterized by the presence of psychotic symptoms such as delusions or hallucinations. The signs and symptoms of schizophrenia are traditionally separated into 2 groups: positive (delusions, hallucinations, and disorganized speech or behavior) and negative (flat affect, avolition, anhedonia, poor attention, and alogia). Schizophrenia is associated with a decline in both cognitive and social functioning that often precedes the development of florid psychosis. The exact etiology of schizophrenia is unknown, although it is thought to be linked to an increase in dopaminergic activity. Treatment includes antipsychotics in conjunction with behavioral therapy.
Swyer syndrome is a disorder of sex development caused by a defect in the SRY gene on chromosome Y. The syndrome is characterized by complete testicular dysgenesis in an individual who has a 46,XY karyotype and is phenotypically female. The presentation of Swyer syndrome is that of a tall female with a normal childhood and development until puberty, which is characterized by primary amenorrhea and no development of secondary sexual characteristics. Management includes hormone replacement therapy and gonadectomy.
Hydrocephalus is a potentially life-threatening condition caused by the excess accumulation of cerebrospinal fluid (CSF) within the ventricular system. Hydrocephalus can be classified as communicating, which is caused by either impaired CSF absorption or excess CSF production; or non-communicating, which is caused by a structural blockage in CSF flow. The causes of hydrocephalus can be congenital or acquired. The clinical presentation is often nonspecific with symptoms including headache, behavioral changes, developmental delays, or nausea and vomiting. If the hydrocephalus is congenital or acquired at a young age, infants often present with macrocephaly. Diagnosis is confirmed with neuroimaging (ultrasound, computed tomography of the head, or magnetic resonance imaging) showing ventriculomegaly. Treatment is most commonly surgical with the placement of a CSF shunt.
Neonatal abstinence syndrome (NAS), or neonatal withdrawal syndrome (NWS), occurs when in-utero addictive substances are suddenly discontinued due to birth. The most common substances include alcohol, nicotine, and rapidly increasing opioids. Some infants can also develop withdrawal symptoms from intrapartum or postnatal exposure to medication used for pain control during labor. Clinical symptoms such as irritability, a high-pitched cry, tremor, fever, poor feeding, and hypertonia can begin within hours of life and vary depending on the substance of exposure and, in some cases, multiple substances. Diagnosis is made by history, clinical presentation, and laboratory findings. Treatment is dependent on the substance(s) of exposure and severity of symptoms. The complications can be lifelong and include growth restrictions, decreased cognition, poor academic achievement, and fetal anomalies as seen in infants with fetal alcohol syndrome.
Kawasaki disease (KD), also known as mucocutaneous lymph node syndrome or infantile polyarteritis, is a medium-sized necrotizing febrile vasculitis that affects children < 5 years of age. Multiple systems are involved but the most serious is the predilection of the coronary arteries. Management involves intravenous immunoglobulin and high-dose aspirin. Follow-up requires serial echocardiograms to monitor for coronary artery aneurysm.
Organ dysfunction resulting from a dysregulated systemic host response to infection separates sepsis from uncomplicated infection. The etiology is mainly bacterial and pneumonia is the most common known source. Patients commonly present with fever, tachycardia, tachypnea, hypotension, and/or altered mentation. Septic shock is diagnosed during treatment when vasopressors are necessary to control hypotension. Sepsis and septic shock are medical emergencies and antibiotics are given within an hour of diagnosis.
Retropharyngeal abscesses occur in the retropharyngeal space, which extends from the base of the skull to the posterior mediastinum. The abscesses occur due to extension of local infections, including upper respiratory infections or localized infections from trauma such as dental procedures. Infections most commonly occur in children. Key clinical features include trismus, dysphagia, and an inability to extend the neck. Diagnosis is confirmed by computed tomography of the neck. Management is primarily through antibiotics and surgical drainage. Complications include airway compromise, mediastinitis, and internal jugular vein thrombosis.
Pertussis, or whooping cough, is a potentially life-threatening highly contagious bacterial infection of the respiratory tract caused by Bordetella pertussis. The disease has 3 clinical stages, the second and third of which are characterized by an intense paroxysmal cough, an inspiratory whoop, and post-tussive vomiting. Pertussis can be prevented by a vaccine that is administered as part of most routine vaccinations and usually started at the age of 6 weeks. Diagnosis is based on the clinical history and confirmed by the detection of the organism via culture or polymerase chain reaction. If pertussis is suspected, immediate antibiotic therapy with macrolides should be initiated, even if laboratory confirmation is pending.
Developmental dysplasia of the hip refers to a range of disorders of the hip joint characterized by hip instability and resulting in subluxation or dislocation that mostly presents during the first few months of life. The condition is often first recognized due to hip laxity on newborn exam. Developmental dysplasia of the hip occurs most commonly in otherwise healthy girls and often does not have an identifiable cause. Treatment is imperative to avoid complications, such as avascular necrosis of the femoral head and pain with mobility. Management is dependent on the severity and age at diagnosis, with infants often treated with a Pavlik harness and children > 6 months of age often requiring open or closed surgical reduction.
Lichen planus (LP) is an idiopathic, cell-mediated inflammatory skin disease. It is characterized by pruritic, flat-topped, papular, purple skin lesions commonly found on the flexural surfaces of the extremities. Other areas affected include genitalia, nails, scalp, and mucous membranes. Exact etiology is unknown but has been found to be associated with hepatitis C infection, other diseases, and multiple drugs. Skin biopsy of the most prominent lesion is used for confirmation of the diagnosis. Cutaneous LP usually resolves in 1–2 years. Other forms, however, are chronic and persistent. Topical corticosteroids are the preferred treatment.
Obstructive sleep apnea (OSA) is a disorder characterized by recurrent obstruction of the upper airway during sleep, causing hypoxia and fragmented sleep. Obstructive sleep apnea is due to a partial or complete collapse of the upper airway and is associated with snoring, restlessness, sleep interruption, and daytime somnolence. The diagnosis relies on medical history, and polysomnography can confirm the diagnosis. Management includes lifestyle changes, methods of positive airway pressure, and surgical intervention.
Hereditary spherocytosis (HS) is the most common type of hereditary hemolytic anemia. The condition is caused by a cytoskeletal protein deficiency in the RBC membrane. This results in loss of membrane stability and deformability of the RBC, giving the cell its spherical shape (spherocyte). These cells are predisposed to splenic degradation, leading to hemolysis. Examination may show jaundice and splenomegaly, while laboratory tests are consistent with hemolytic anemia and increased hemoglobin concentration. Among multiple confirmatory tests for HS, the eosin-5’-maleimide (EMA) binding test is preferred. The only definitive treatment for HS is splenectomy.
Wound healing is a physiological process involving tissue repair in response to injury. It involves a complex interaction of various cell types, cytokines, and inflammatory mediators. The overall process protects underlying structures from further damage. Wound healing stages include hemostasis, inflammation, granulation, and remodeling. Certain conditions such as diabetes, peripheral vascular disease, and malnutrition can limit the body’s ability to heal itself, thus resulting in complications.
Disease surveillance is an important and fundamental part of public health. Different epidemiologic measures are used to inform health care providers and policy-makers about the incidence rates, cumulative incidence, attack rates, prevalence, and person-time at risk of a disease or condition. Surveillance can help determine the cause of a disease as well as monitor the risks for developing that disease. Surveillance also follows changes in the levels of risk, thereby providing guidance for developing and implementing programs for disease prevention and control.
Disease surveillance is an important and fundamental part of public health. Different epidemiologic measures are used to inform health care providers and policy-makers about the incidence rates, cumulative incidence, attack rates, prevalence, and person-time at risk of a disease or condition. Surveillance can help determine the cause of a disease as well as monitor the risks for developing that disease. Surveillance also follows changes in the levels of risk, thereby providing guidance for developing and implementing programs for disease prevention and control.
Malaria, a vector-borne parasitic disease caused by Plasmodium spp., is transmitted via injection of sporozoites or immature forms of the parasite into a person's bloodstream. Sporozoites then infect the hepatocytes and differentiate into schizonts, which subsequently rupture, and merozoites invade red blood cells. As such, pharmacotherapy for malaria targets exoerythrocytic and erythrocytic forms of schizonts. Collectively, these agents are classified as schizonticides.
The arm is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior) and houses numerous structures, including the humerus; the brachial and profunda brachii arteries; the basilic, cephalic, and brachial veins; the radial, median, ulnar, and musculocutaneous nerves; and the flexor and extensor muscles of the arm.
Vaccination is the administration of a substance to induce the immune system to develop protection against a disease. Unlike passive immunization, which involves the administration of pre-performed antibodies, active immunization constitutes the administration of a vaccine to stimulate the body to produce its own antibodies. A vaccine is usually an antigenic, non-virulent form of a normally virulent microorganism. Vaccinations are a form of primary prevention and are the most effective form due to their safety, efficacy, low cost, and easy access. While the majority of vaccines are administered to young patients, some vaccines are targeted to diseases that occur in middle and old age, and are therefore administered to older patients.
Hypertrophic pyloric stenosis is hypertrophy and hyperplasia of the pyloric sphincter muscle. The condition is the most common cause of gastrointestinal obstruction in infants. Affected newborns typically present after the third to fifth week of life with progressive non-bilious vomiting and a firm, olive-like mass in the epigastrium. Ultrasound confirms the diagnosis based on the thickness and length of the pyloric muscle and channel diameter. Initial treatment consists of fluid resuscitation with correction of electrolyte imbalances, followed by either open or laparoscopic pyloromyotomy.
Diabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of DI: central DI (CDI) and nephrogenic DI (NDI). In CDI, the amount of antidiuretic hormone (ADH) produced by the hypothalamus or released from the pituitary gland is decreased. In nephrogenic DI, the kidneys fail to respond to circulating ADH. Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia. Central and NDI are differentiated based on measured ADH levels and response to a water deprivation test. Central DI is treated with desmopressin, while nephrogenic DI is treated with diuretics and dietary salt restriction.
Epidemiological studies are designed to evaluate a hypothesized relationship between an exposure and an outcome; however, the existence and/or magnitude of these relationships may be erroneously affected by the design and execution of the study itself or by conscious or unconscious errors perpetrated by the investigators or the subjects. These systematic errors are called biases. If not avoided or accounted for, biases can completely invalidate the results of an otherwise well-thought-out study.
Raynaud's phenomenon refers to an abnormally marked and sudden vasoconstrictive response to cold temperature or emotional stress. The condition was first described by a medical student, Maurice Raynaud, in 1862. These "vasospastic attacks" are usually but not always limited to the fingers or toes and are associated with sharply demarcated triphasic color changes at the distal portions of the digits. There is initial blanching with numbness, followed by cyanosis, both of which correspond to the phase of constricted blood flow; subsequently, there is a red blush of reperfusion after rewarming or resolution of the provocative stressful event. Raynaud's phenomenon may be primary (idiopathic) or secondary.
Esophageal cancer is 1 of the most common causes of cancer-related deaths worldwide. Nearly all esophageal cancers are either adenocarcinoma (commonly affecting the distal esophagus) or squamous cell carcinoma (affecting the proximal two-thirds of the esophagus). Major risk factors for adenocarcinoma include smoking, obesity, and Barrett’s esophagus. For squamous cell carcinoma, risk factors include smoking, alcohol consumption, and certain dietary factors. Early-stage cancer is often asymptomatic, with dysphagia and weight loss presenting as the disease progresses. Diagnosis is by endoscopic biopsy or image-guided biopsy of the metastatic site. Management depends on the disease stage. Options include surgical resection, chemotherapy, and radiation. For unresectable esophageal cancers, palliative measures are provided for symptom relief and to prolong survival.
The elbow is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm. The elbow consists of 3 joints, which form a functional unit enclosed within a single articular capsule. The elbow is the link between the powerful motions of the shoulder and the intricate fine-motor function of the hand. To provide that link, the motions of the elbow include extension and flexion as well as pronation and supination of the forearm.
Cystic fibrosis is an autosomal recessive disorder caused by mutations in the gene CFTR. The mutations lead to dysfunction of chloride channels, which results in hyperviscous mucus and the accumulation of secretions. Common presentations include chronic respiratory infections, failure to thrive, and pancreatic insufficiency. The gold standard for diagnosis is the sweat chloride test, which can be complemented by genetic testing. Cystic fibrosis ultimately leads to chronic inflammation and multisystem organ failure. Management includes CFTR modulator therapy and system-specific strategies for supportive care. Prognosis varies depending on treatment and complications. With optimal medical care, patients can live into their mid-40s.
Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Ultrasound can visualize the thrombus and anticoagulation is the primary mode of treatment; the main objective is the prevention of development of a PE.
The development of the embryonic cardiovascular system begins during the 3rd week of gestation. The process begins with a straight tube, which will eventually differentiate to form a functional heart after several events. Disturbances of any events in the development of the heart, such as cardiac looping, can result in severe congenital disorders. The major clinical presentation of these abnormalities will be cyanosis.
Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. The most common symptoms include tachycardia, tachypnea, hypotension, altered mentation, and oliguria. Treatment measures vary depending on the suspected cause of shock and may include mechanical ventilation, IV crystalloids, vasopressors, and blood transfusion.
An aortic aneurysm is the abnormal dilation of a segment of the aorta. Abdominal aortic aneurysm is the most common aortic aneurysm, occurring frequently in the infrarenal area. Degenerative aortic disorders are the prevalent etiology, affecting patients > 60 years of age. Most aneurysms are asymptomatic, but can cause compression of surrounding structures or rupture, which is a life-threatening emergency. Diagnosis is often made by ultrasound. As aneurysmal rupture carries a high mortality rate, surveillance is recommended for asymptomatic cases to monitor aortic diameter. Elective surgery (the majority via endovascular aortic repair) is an effective way to reduce complications and aneurysm-related death. This surgery is performed based on aortic size, underlying condition, and associated symptoms.
Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy.
Achalasia is a primary esophageal motility disorder that develops from the degeneration of the myenteric plexus. This condition results in impaired lower esophageal sphincter relaxation and absence of normal esophageal peristalsis. Patients typically present with dysphagia to solids and liquids along with regurgitation. Diagnosis is established by high-resolution manometry. To rule out malignancy as a cause of achalasia, upper endoscopy is performed. Barium swallow study helps evaluate the esophageal morphology. Management options include pneumatic balloon dilation, surgical myotomy, and botulinum toxin injection. Choice of treatment is dependent on the type of achalasia and surgical risk. Medications are available for those who fail initial intervention; however, they provide the least benefit.
Scabies is an infestation of the skin by the Sarcoptes scabiei mite, which presents most commonly with intense pruritus, characteristic linear burrows, and erythematous papules, particularly in the interdigital folds and the flexor aspects of the wrists. Direct and prolonged human-to-human contact is the biggest risk factor for transmission. Diagnosis is most often clinical but can be confirmed by microscopic examination of skin scrapings or by dermatoscopy. Treatment includes permethrin cream for both the patient and close personal contacts (cohabitants and sexual partners) as well as thorough cleaning of bedding and clothing.
Retinoblastoma is a rare tumor but the most common primary intraocular malignancy of childhood. It is believed that the condition arises from a neuronal progenitor cell. Retinoblastoma can be heritable or nonheritable. The condition typically presents as unilateral or bilateral leukocoria (abnormal white reflection in the eye) in a child under the age of 2. Retinoblastoma is fatal if not treated but early recognition accounts for a high survival rate in resource-rich countries.
Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. The kidneys can also be affected, and urate crystals can precipitate as chalkstone-like deposits (“tophi”) in the soft tissues, synovial tissues, or in bones near the joints. Hyperuricemia is due to overproduction and/or underexcretion of uric acid and is a necessary but insufficient precondition to developing urate crystal deposition disease (most hyperuricemic individuals never experience clinical gout). The most commonly involved joint is the first metatarsophalangeal joint. The identification of urate crystals in joint aspirate or tophi is diagnostic.
Effective therapies to relieve the pain of a gout flare include nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, and glucocorticoids; the choice of therapy depends on the individual and if there are any contraindications.
The citric acid cycle, also known as the tricarboxylic acid (TCA) cycle or the Krebs cycle, is a cyclic set of reactions that occurs in the mitochondrial matrix. The TCA cycle is the continuation of any metabolic pathway that produces pyruvate, which is converted into its main substrate, acetyl-CoA. The TCA cycle oxidizes acetyl-CoA and produces 2 CO2, GTP, 3 NADH + H+, and FADH2. Its end products (NADH + H+ and FADH2) are passed into the electron transport chain to yield a total of 10 ATP per cycle.
The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism (carbohydrates, proteins, lipids, hormones), nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. The liver can be divided into 4 lobes or 8 segments. Microscopically, it is divided into hepatic lobules. Its main neurovascular bundle is found within the transverse fissure of the liver, also called the porta hepatis.
Interstitial lung diseases are a heterogeneous group of disorders characterized by the inflammation and fibrosis of lung parenchyma, especially the pulmonary connective tissue in the alveolar walls. It may be idiopathic (e.g., idiopathic pulmonary fibrosis) or secondary to connective tissue diseases, medications, malignancies, occupational exposure, or allergens. Interstitial lung diseases commonly present with progressive exertional dyspnea and dry cough. Pulmonary function testing shows a restrictive lung disease pattern. Lung high-resolution computed tomography and biopsy usually establish the diagnosis. Treatment includes steroids and immunosuppressives.
Wilson disease (hepatolenticular degeneration) is an autosomal recessive disorder caused by various mutations in the ATP7B gene, which regulates copper transport within hepatocytes. Dysfunction of this transport mechanism leads to abnormal copper accumulations in the liver, brain, eyes, and other organs, with consequent major and variably expressed hepatic, neurologic, and psychiatric disturbances. Liver involvement may manifest as hepatitis, liver failure, or cirrhosis, while basal ganglia involvement causes the extrapyramidal signs. Most patients are diagnosed between the ages of 5 and 35 years (mean: 13 years). Diagnosis is established if the patient has low plasma ceruloplasmin, corneal deposits of copper (Kayser-Fleischer rings), and elevated copper levels in the urine. However, other tests are often needed since not all patients will have all these findings. The prognosis is good for patients without advanced liver disease and who are treated with the chelating agents penicillamine or trientine. Untreated Wilson disease is ultimately fatal, with patients dying from cirrhosis, acute liver failure, or complications due to progressive neurologic disease.
Impetigo is a highly contagious superficial bacterial infection typically caused by Staphylococcus aureus (most common) and Streptococcus pyogenes. Impetigo most commonly presents in children aged 2 to 5 years with lesions that evolve from papules to vesicles to pustules, which eventually break down to form characteristic “honey-colored” crusts. Infection can either be primary (bacterial infection of healthy, intact skin) or secondary (infection of pre-existing abrasions). The diagnosis is clinical, and management includes topical or systemic antibiotic therapy. Complications of impetigo include post-streptococcal glomerulonephritis, cellulitis, and scarlet fever.
Conjunctivitis is a common inflammation of the bulbar and/or palpebral conjunctiva. It can be classified into infectious (mostly viral) and noninfectious conjunctivitis, which includes allergic causes. Patients commonly present with red eyes, increased tearing, burning, foreign body sensation, and photophobia. Itching is a chief symptom in allergic conjunctivitis. Treatment depends on the underlying cause and includes antibiotic and antiviral therapy, glucocorticoids, and antihistamines.
The orbit is the cavity of the skull in which the eye and its appendages are situated. The orbit is composed of 7 bones and has a pyramidal shape, with its apex pointed posteromedially. The orbital contents comprise the eye; orbital and retrobulbar fascia; extraocular muscles; cranial nerves II, III, IV, V, and VI; blood vessels; fat; lacrimal gland with its sac and nasolacrimal duct; eyelids; palpebral and suspensory ligaments; ciliary ganglion; and short ciliary nerves.
Fibroadenomas are the most common benign tumor of the female breast and the most common breast tumor in adolescent and young women. The tumors are well-circumscribed, mobile, and unencapsulated, with a rubbery or firm consistency. Fibroadenomas are hormonally responsive, so they may increase in size during pregnancy and usually regress after menopause. Histologically, fibroadenomas are composed of a biphasic proliferation of both glandular and stromal elements. Fibroadenomas are associated with a slightly increased risk of carcinoma, with a somewhat higher risk if so-called “complex” features are present. Diagnosis is based on physical findings and ultrasonography. Management is based on regular checkups to monitor growth.
Ankle pain accounts for up to 20% of cases of musculoskeletal complaints in outpatient clinics. The most common etiologies of foot and ankle pain can be categorized into arthritis, trauma, sprains, and systemic causes. The diagnosis is clinical with imaging and/or laboratory studies to confirm the suspected diagnosis. Management involves rest, ice packs, compression, elevation, and nonsteroidal anti-inflammatory drugs (NSAIDs). Surgical repair is rarely needed.
Infectious folliculitis is a common skin condition characterized by the inflammation of hair follicles caused by an infectious agent (bacterial, fungal, viral, or parasitic). Staphylococcus aureus is the most common causative agent. Diagnosis is clinical and presentations include pruritus, follicular pustules, and erythematous papules. Management is usually supportive care but topical or oral antibiotic therapy may be required in severe cases.
Fever is defined as a measured body temperature of at least 38℃ (100.4℉). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. This process increases the physiologic “set-point” of body temperature. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever is a symptom of a wide array of diseases; therefore, an accurate history and review of other symptoms are crucial in finding the cause. The major etiologies of fever include infectious (most common), non-infectious, neurogenic, and drug-induced. High fever can have systemic effects that put the individual at risk of both short- and long-term dysfunction. In severe cases, fever may lead to death if untreated.
Female sexual dysfunction represents a variety of disorders in any part of the sexual response cycle, including desire disorders, arousal disorders, orgasmic disorders, and pain disorders. The condition may result from stresses and interpersonal conflicts as well as physical illness or medication/substance use. These disorders cause significant distress to the patient and her partner. Treatment options include psychotherapy, physical therapy, and pharmacotherapy.
Typhoid (or enteric) fever is a severe, systemic bacterial infection classically caused by the facultative intracellular and Gram-negative bacilli Salmonella enterica serotype Typhi (S. Typhimurium, formerly S. typhi). S. paratyphi serotypes A, B, or C can cause a similar syndrome. Up to 20 million new cases of typhoid fever occur each year worldwide, most commonly in undeveloped areas with poor sanitation. Transmission occurs through the fecal-oral route, and humans are the only known reservoir. Complications of typhoid fever include intestinal hemorrhage, pericarditis, visceral abscesses, and septicemia. Treatment is with fluoroquinolones. Prevention of typhoid fever is available through vaccination, hand hygiene, and safe food and water practices.
Erythema nodosum is an immune-mediated panniculitis (inflammation of the subcutaneous fat) caused by a type IV (delayed-type) hypersensitivity reaction. It commonly manifests in young women as tender, erythematous nodules on the shins. The underlying etiology varies and may be associated with infection, drug exposure, irritable bowel disease, pregnancy, or malignancy. The lesions often self-resolve within 8 weeks without scarring. Management focuses on identifying and treating the underlying cause.
Erythema multiforme (EM) is an acute hypersensitivity reaction characterized by targetoid skin lesions with multiple rings and dusky centers. Lesions may be accompanied by systemic symptoms (e.g., fever) and mucosal lesions (e.g., bullae). The majority of patients with EM have a history of recent viral (especially herpes simplex virus) or bacterial infection (usually Mycoplasma pneumoniae). Erythema multiforme is diagnosed clinically and treatment is directed toward the causative agent and alleviation of symptoms.
Croup, also known as laryngotracheobronchitis, is a disease most commonly caused by a viral infection that leads to severe inflammation of the upper airway. It usually presents in children < 5 years of age. Patients develop a hoarse, “seal-like” barking cough and inspiratory stridor. Human parainfluenza viruses account for the majority of cases, followed by respiratory syncytial virus, adenovirus, rhinovirus, and enteroviruses. Croup is usually diagnosed clinically or with the aid of X-ray imaging (steeple sign). Treatment consists of steroids and epinephrine.
Mallory-Weiss syndrome (MWS) is defined by the presence of longitudinal mucosal lacerations in the distal esophagus and proximal stomach, which are usually associated with any action that provokes a sudden rise in intraluminal esophageal pressure, such as forceful or recurrent retching, vomiting, coughing, or straining. Hematemesis results from bleeding from submucosal blood vessels and is self-limited in 80%–90% of patients. Treatment includes gastric acid suppression, endoscopic intervention, and angiotherapy if there is active bleeding. Blood transfusions and surgery are not usually required.
Pericarditis is an inflammation of the pericardium, often with fluid accumulation. It can be caused by infection (often viral), myocardial infarction, drugs, malignancies, metabolic disorders, autoimmune disorders, or trauma. Acute, subacute, and chronic forms exist. Acute pericarditis is usually idiopathic and manifests as fever, pleuritic chest pain, and an audible pericardial rub by auscultation. Diffuse upwardly concave ST-segment elevations in the initial ECG and pericardial effusion on echocardiography confirm the diagnosis. Acute pericarditis is usually self-limiting (2–6 weeks); therefore, management is conservative. If cardiac tamponade or constrictive pericarditis develops, cardiac output can be severely reduced. Treatment depends on the cause, but general measures include analgesics, anti-inflammatory drugs, colchicine, and rarely surgery.
Autoimmune hepatitis (AIH) is a rare form of chronic liver disease in which the immune system attacks the liver causing inflammation. It predominantly affects women. Clinical presentation ranges from asymptomatic cases to patients that present with symptoms of acute liver failure (jaundice, right upper quadrant pain). Because AIH has a 40% mortality in 6 months without treatment, early diagnosis and treatment are imperative. Diagnosis is established by detecting anti-smooth muscle antibodies and performing a confirmatory liver biopsy. Treatment includes corticosteroids and azathioprine. If treatment is initiated early in the disease course, the prognosis is favorable.
Transmissible spongiform encephalopathies are diseases caused by prions. Prions differ from viruses in that they are small, infectious pathogens that do not contain nucleic acid. Recognized spongiform encephalopathies include Creutzfeldt-Jakob Disease (CJD), variant Creutzfeldt-Jakob Disease (vCJD), Kuru, fatal familial insomnia (FFI), and Gerstmann-Straussler syndrome (GSS). Common characteristics of these diseases include dementia, ataxia, and myoclonus. Unfortunately, these diseases are associated with long incubation periods (20+ years) and once symptoms occur, rapidly progress to death.
Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. There are many conditions that can cause AF, usually damage to the heart (e.g., coronary artery disease, previous myocardial infarction). Diagnosis is confirmed by an electrocardiogram that will show an “irregularly irregular” heartbeat with no distinct P waves and narrow QRS complexes. AF increases the risk of thromboembolic events. Treatment is primarily based on ventricular rate and rhythm control, which can be achieved through drugs and/or cardioversion. Anticoagulation is administered if the patient is at significant risk for thromboembolic events.
Gynecomastia is a benign proliferation of male breast glandular ductal tissue, usually bilateral, caused by increased estrogen activity, decreased testosterone activity, or medications. The condition is common and physiological in neonates, adolescent boys, and elderly men. Some cases are pathological or secondary to chronic liver disease, kidney disease, or hyperthyroidism. The majority of cases are asymptomatic and do not need treatment.
Epiglottitis (or “supraglottitis”) is an inflammation of the epiglottis and adjacent supraglottic structures. The majority of cases are caused by bacterial infection; however, several viral and fungal pathogens have been identified, depending on the patient’s immune status and age. Symptoms are rapid in onset and severe. Without treatment, epiglottitis can cause life-threatening airway obstruction that presents with difficulty breathing, stridor, and cyanosis. Diagnosis is mainly clinical but can be confirmed by pharyngoscopy. The focus of treatment is airway management and administration of antibiotics.
COVID-19, also known as Coronavirus disease, is a respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2). Transmission mainly occurs via direct contact or aerosol droplets. The disease may present asymptomatically or with fever and dry cough.
Fractures of the cervical spine are common in polytrauma patients. Any patient presenting with neck pain post-trauma should be evaluated for the possibility of a cervical spine injury and/or fracture. Cervical spine fractures are more common in young men and are commonly seen in those injured in automobile accidents. In this article, we will focus on cervical spine fractures and the common forms of spinal cord injuries associated with such fractures.
Ovarian torsion is defined as the complete or partial rotation of the adnexal supporting organ around its axis.
It is associated with blood supply compromise and ischemic injury in the ovary which occurs following reduced venous return that causes edema of the ovarian tissue, hemorrhage and compromised arterial supply that leads to death of the tissues.
Most cases of ovarian torsion involve both the ovaries and the fallopian tubes. Isolated ovarian or fallopian tube torsion is rare and has an estimated incidence of one in 1.5 million women.
The hyperosmolar hyperglycemic state is characterized by severe hyperosmolality, hyperglycemia, and dehydration. Patients in a hyperosmolar hyperglycemic state do not have ketoacidosis. Diabetic ketoacidosis, on the other hand, is characterized by hyperglycemia, dehydration, and acidosis due to ketone bodies accumulation in the blood; thus, the condition was also known as hyperosmolar non-ketotic state (HONKS) or non ketotic hyperosmolar states (NKHS)
Head injuries can be generally classified into serious or non-serious. Non-serious head injuries account for the majority of the cases. In the United States, the estimated annual incidence of non-serious head injuries is around 1300 per 100,000. In the following article, you will learn everything about the symptoms of traumatic brain injury and understand the principles of minor and major head injuries.
Cerebral edema is a common condition that usually presents as a consequence of a local or systemic pathology rather than a primary condition. Cerebral edema is defined as the excess accumulation of water in the intracellular and extracellular spaces of the brain. In this article, you will get a great overview of the types and medical treatment of cerebral edema.
Altered mental status (AMS) is a common presentation to the emergency department that comprises a group of clinical symptoms rather than a specific diagnosis. Patients with AMS present with cognitive, attention, arousal, or consciousness disruption. To understand emergency medicine, you should gain essential information about altered mental status.
The eyes can be affected by a number of congenital malformations which can present as an isolated anomaly or in a syndromic association. In this article, we will cover some common congenital malformations of the eye and the ocular adnexa.
At the emergency department, it is quite common to see a patient presenting with seizures. In this article, we will cover the following topics: seizures’ management at the emergency department, management and diagnostic workup for the first seizure, and epilepsy emergencies.
Rheumatic diseases are related to or caused by an abnormal immune response that commonly involves autoantibodies. The detection of these autoantibodies in the laboratory evaluation of a patient suspected to have a rheumatic disease can help in confirming the diagnosis and monitor the prognosis or response to treatment in rheumatic diseases.
Diabetic ketoacidosis is a common problem in type 1 diabetics and can be the presenting feature of newly-diagnosed diabetes. The typical patient with diabetic ketoacidosis is an adolescent or a child who is ill and who is presenting to the emergency department. In this article, you will gain a great overview of the diabetic management at the emergency department.
In this article, we will cover the most common diseases of the biliary tract. Because this is an introductory article, we will only discuss the definition of such diseases, the clinical presentation, and the diagnostic workup.
In this article, we will talk about the microscopic anatomy part of the kidney known as the collecting duct system. The collecting duct system consists of a series of tubules and ducts that connect the nephrons to a minor calyx or to the renal pelvis. This collecting duct system, as the name implies, is responsible for the reabsorption and excretion of different electrolytes and for fluid balance in our bodies “collecting”.
Antiplatelet agents are medications that inhibit platelet aggregation, a critical step in the formation of the initial platelet plug. Abnormal, or inappropriate, platelet aggregation is a key step in the pathophysiology of arterial ischemic events. The primary categories of antiplatelet agents include aspirin, ADP inhibitors, phosphodiesterase/adenosine uptake inhibitors, and glycoprotein IIb/IIIa inhibitors. Common indications for antiplatelet agents include the treatment and prevention of ischemic heart disease and stroke, peripheral artery disease, and other conditions associated with a high risk for arterial thrombosis.
Potter syndrome, also known as the Potter sequence refers to the specific appearance of the baby due to oligohydramnios which is a decrease in amniotic fluid volume which causes deformities in the fetus while in the uterus. These deformities include flattened nasal bridge, epicanthal folds, low set ears and bowed legs. It also leads to pulmonary hypoplasia. The cause has decreased the production of amniotic fluid which is required to cushion the baby against the uterine walls.
In this article, we will cover mainly the aging and age-related disorders of the retina, lens and vitreous body. Hypertensive retinopathy is a condition that is characterized by retinal vascular changes in people with elevated blood pressure. The screening for, detection, and documentation of hypertensive retinopathy in patients with established hypertension is currently considered as standard in the care of patients with high blood pressure.
In this article, you will gain a perfect overview of the distal convoluted tubule, the portion of the nephron of the kidney extending from the loop of Henle up to the collecting duct system. Furthermore, you will learn about the pathophysiology and treatment of the autosomal recessive disorders called Gitelman syndrome and Bartter syndrome for the perfect medical exam preparation.
Unilateral agenesis is defined as the complete absence of development of one kidney and ureter. The condition is usually silent and is usually detected on fetal ultrasound scan by the presence of empty renal fossa. The incidence of URA is relatively common and is due to genetic as well as maternal causes. Human renal development is initiated by the 5th week of gestation and renal agenesis occurs when the ureteric bud fails to form the ureter, the renal pelvis, and renal mesenchyme. URA is often associated with anomalies of the contralateral kidney and ureter as well.
Categorical data refers to that type of data which can be classified into groups. There are various tools and techniques that are used to analyze categorical data: pie-charts, bar charts and two-way tables (for stand-alone categorical data analysis); Chi-square test and Diagnostic-odds-ratio test (for two categorical variable relationship analysis); logistic, probit and OLS (for categorical dependent variable analysis); and simple regression (for categorical independent variable analysis).
It is common to detect proteinuria during routine urinalysis in children. Although transient proteinuria and orthostatic proteinuria are common and benign conditions, it is important to differentiate them from clinically significant proteinuria associated with renal pathology or systemic diseases. Such differentiation can be made by considering the clinical presentation and appropriate use of laboratory tests. Treatment of proteinuria usually includes that of underlying condition along with consideration of proteinuria lowering medications when indicated.
Pathology makes up about 70 % of your USMLE Step 1 prep: If you're like most students, you're probably struggling to find the right approach that works when it comes to getting started, gaining the required knowledge, and applying what you've learned so that you're really ready for test day! This article will guide you through the entire process of Pathology board exam preparation. It takes a very structured and integrated 3-step approach. You can be fully prepped in about 40 days if you study for an average of 6 hours per day – Start now!
This article discusses the concept of ‘association’ in biostatistics. Measures of association assume categorical or continuous level of data. The article also discusses in detail three kinds of risks and odd ratio. Attributable risk is also known as excess risk which is calculated when individuals or subjects in a research are assembled on exposure status. Population attributable risk is also discussed which indicates reduction in an incidence which may be observed in case the whole population were completely unexposed.
This article discusses measures of association, causality relationship and different possibilities in a causal relationship. The Bradford Hill criteria comprising nine principles is also being discussed. The possibilities of a causal relationship include four principles. The article also explains reliability, validity, and related characteristics. The major threats to reliability discussed in the article include poor sampling, instability and divergence.
Mendel, an Austrian monk, worked on basic concepts in genetics which were not recognized until after his death. Rediscovery of Mendelian genetics paved the path for modern genetics. His concepts heavily relied on test crosses and the rules of probability. The addition and multiplication rules are applied to mutually elusive and independent cases, respectively. However, modern genetics is an exception from Mendel’s genetics. Discovery of multigene inheritance, multiple alleles, dominance variations and epistasis has changed the face of classical genetics to a great deal.
This article discusses the sampling distribution of mean and proportion in detail. The sampling error, sampling variability, and normal model for proportion are explained with examples. A central limit theorem which states that if the number of the sample size is large, it results in the normal distribution of mean of sample size of ‘n’ number of population, and is also included in this article. The sampling proportion of distribution and CLT has three conditions to be fulfilled for accurate computation purpose.
Regression is used to analyze the impact of certain variables (i.e., the independent variables) on some other variables (i.e., the dependent variables). Simple linear regression is used when there is one dependent and one independent variable. The multiple linear regression (MLR) method is used when there is more than one independent variable. OLS, logistic and probit regression are used when dependent variable is binary. Random effect and fixed effect regression is used when analyzing panel data.
Inferences for population mean are made using a sample mean when the population mean is unknown. There are, broadly, three ways to make inferences related to population mean: point estimation (i.e., sample mean and mean of the sampling distribution); interval estimation (i.e., confidence intervals); and hypothesis testing (i.e., two-tailed tests, upper-tailed tests, and lower-tailed tests). These methods use z-distribution when the population standard deviation is known and the t-distribution when it’s not known.
This article discusses the estimation of proportion using intervals which are used to make a measure of results for the entire population using a range of reasonable values for the population proportion. The other areas of hypothesis testing discussed in this article include the creation of a confidence interval and four steps of constructing an interval. The article also introduces terms such as confidence, margin of error, critical values and a trade-off between confidence and precision.
Categorical data refers to that type of data which can be classified into groups. There are various tools and techniques that are used to analyze categorical data: pie-charts, bar charts and two-way tables (for stand-alone categorical data analysis); Chi-square test and Diagnostic-odds-ratio test (for two categorical variable relationship analysis); logistic, probit and OLS (for categorical dependent variable analysis); and simple regression (for categorical independent variable analysis).
Congratulations on your decision to become a physician! The road from college to attending physician is a long and sometimes torturous one with road blocks and hurdles. This eBook is designed to guide you through the logistical and strategic portions of the process.
Our musculoskeletal system is a complex machinery of bones, joints, muscles, and their auxiliaries, which serve as the body's supporting structure and give the body the ability to move. Our skeletal muscles provide the moving strength and may be low or high in their muscle tone. They have different courses from origin to insertion and also differ in their function. In the following article, you will receive a concise overview of 10 important muscles of our musculoskeletal system.
This article has explained the concepts of variables and data levels of measurement. There are two types of variables i.e continuous and discrete. The four scales of data measurement used in statistics are nominal, ordinal, internal and ratio measurement. Causality refers to a relation between two variables. The article has also discussed frequency and normal distribution along with examples. Central limit theorem and type I and II errors are also part of this article
The article has discussed the history and background of medical and research ethical reforms. The ethical reforms include the Nuremberg Code, the Declaration of Geneva, and the Hippocratic Oath. The reforms also include “The Belmont Report” resulting from the Tuskegee Syphilis Study. The declaration of Helsinki ties together the Nuremberg code and the declaration of Geneva. The article has also discussed pillars of research ethics and the Research Ethics Board in detail.
Bipolar disorder is a psychiatric illness characterized by periods of depression and mania/hypomania. It affects approximately 1% of the general population. The disease results from genetic mutations precipitated by environmental factors. Clinically, it varies from manic features of hyperactivity and irritability, to depressive episodes with reduced activity, lethargy and loss of interest, and a mixed picture of manic and depressive episode features. Treatment of bipolar disease involves pharmacotherapy with mood stabilizers, behavioral therapy, and electroconvulsive therapy. Mortality and morbidity are mainly due to the associated suicidal and homicidal tendencies.
The leading cause of death in the United States is cardiovascular disease, which has been long connected to dyslipidemia in general and hyperlipidemia in particular. Half of the American population are found to have hypercholesterolemia, while one-third of people in the United States have an elevated level of the so-called bad cholesterol known as low-density lipoprotein (LDL) cholesterol. Because of this, a significant number of those who seek medical attention in the primary care setting are expected to have some sort of hyperlipidemia that needs to be corrected.
Genomics is the study of the genetic material of organisms. It includes the study of methods for knowing the location and sequence of genes. Alternative splicing is a method for gene expression that results in the formation of multiple proteins from a single gene. DNA sequence may include coding and non-coding sequence. BRCA2 gene is an important gene that codes for a protein which helps maintain genetic information by DNA repair.
The Boveri–Sutton chromosome theory states that the chromosomes are the basis of all genetic inheritance. Morgan's work with fruit flies provides a solid evidence associating a specific gene with a specific chromosome. The SRY gene is important in the sex determination of humans. It encodes a SRY protein which is responsible for male sex determination initiation. Certain human genetic disorders are sex-linked, such as color blindness and hemophilia. There are two exceptions to the chromosome theory of inheritance.
This article discusses screening tests in detail. Screening tests are conducted in order to find out or identify any disease or calamity in a person before realization of its related symptoms. It is of major importance when it is used to identify diseases which are deadly and are desired to be cured timely to avoid any dangerous consequences. The article discusses various elements of a screening test including sensitivity, specificity, false positive and negative results, positive predictive value (PPV), negative predictive value (NPV) along with examples.
An aortic aneurysm is the abnormal widening of a part of the wall of the aortic artery leading to abnormal bulging out with or without a cause. An aortic aneurysm is a localized or diffused dilation of aortic artery usually more than 50% of its normal size. Aortic aneurysms can be classified into thoracic and abdominal aortic aneurysm with different clinical features, diagnostic criteria and management. If this bulging occurs continuously, it can result in the bursting of the artery and, eventually, haemorrhage, a condition termed as aortic dissection, which is considered a catastrophic fatal condition. Abdominal aortic aneurysms are generally caused due to infection, injury or atherosclerosis. Thoracic aortic aneurysms are caused due to injury, high blood pressure, and inherited tissue disorders.
As a physician, you could not work without models in medicine: The consequences would be chaos, randomness, and a lack of structure. On the other hand, one should not fixate on just one model in order to prevent a limited diagnostic and therapeutic spectrum. An old medical rule says: Anything helpful should be considered. Below, we are summarizing the five most important groups of models at a glance: behavioral models, bios-psychological models, the psychodynamic model, social-psychological models, and sociological models. With this, you will be perfectly prepared for exams and the preliminary examination.
Everybody is constantly exposed to small amounts of radioactive, and thus ionizing radiation. Some energy-rich radiation reaches Earth from space, slowed down by the atmosphere, but naturally radioactive substances exist here as well. In the world of medicine, radiation is used in many forms of therapy, such as X-ray exams at the dentist's office, a suspected broken bone or mammography.
Eating disorders like anorexia nervosa, bulimia nervosa, and the binge eating disorder are common diseases. Exact knowledge of the pathogenesis and symptoms of these diseases, which mostly affect young women, is crucial for a correct diagnosis and treatment. This article will help you to correctly diagnose the different eating disorders in both the second state exam and in professional life later on.
Many young couples suffer from an unfulfilled wish to bear children. Men, as well as women, may be the physiological cause of this barrenness; regardless, undesired childlessness always implies a great amount of emotional distress for both partners. The diagnostic process involves extensive testing of both the man and the woman, including a hormone analysis of the blood and physical examinations. The terminological distinction between sterility and infertility has to be considered. Treatment consists in artificial insemination techniques, such as IVF or ICSI.
During puberty, a child’s body matures into the body of an adult. During this process, pathological faults can occur. An early onset of puberty might, for example, cause dwarfism. Psychological stress of the patients is not negligible and should be taken into consideration in medical consultation. The following article provides soon-to-be physicians with a summary of puberty and its malfunctions, so that a correct diagnosis and treatment can be conducted.
Porphyrias are a group of metabolic disorders, at the bottom of which lies a disturbance in the synthesis of the heme; thereby, in most cases, it is about a hereditary enzyme defect. The disease patterns differ depending on the affected enzyme; one clinically differentiates between acute and non-acute forms. In particular, a physician should also be aware of the two most common forms of overall rare diseases as an important differential diagnosis. Below is thus an overview of the clinical manifestations, diagnosis and treatment options of the porphyria.
Spinal disc herniation is a common cause for pain syndromes in the cervical and lumbar spine. It is the most common trigger for radiculopathies which lead to pain and disturbances of sensation of the dermatomes but can also be accompanied by pareses and loss of reflexes. Both for your examinations as well as in everyday clinical life, knowledge of radicular syndromes as well as their diagnosis and treatment are highly meaningful.
EDS — a clinically heterogeneous syndrome involving a genetic defect in connective tissue structure and synthesis, specifically collagen that affects joints, skin and blood vessels, is a group of inherited disorders characterized by stretchy, fragile skin and extremely flexible joints. An even severe form of the disease involves the blood vessels and is called vascular Ehlers-Danlos syndrome. Prognosis is clearly guided by the type of EDS, however there is no cure for the disease.
Milestones of various ages provide a predictable pattern in infants and children concerning the development of their skills in each age group. Understanding of the normal child development helps clinicians to identify any symptom of delayed child development. Early identification of the developmental delays can prevent future complications, and the child can be timely referred for therapeutic services. The aim is to promote healthy development. Developmental milestones have been established in physical, social, verbal and cognitive domains.
Dermatofibroma, or benign fibrous histiocytoma, is a common cutaneous nodule that may be superficial or deep. It is the most common painful skin tumor, mostly affecting women. Although, the precise underlying etiology and mechanism for the development of this skin pathology is not well known, it is believed to be a neoplastic process owing to its clonal proliferation growth. While the patients may usually be asymptomatic, the tumor growth may exhibit rapid growth or may remain static for several years. An intervention is not called for unless the patient is symptomatic.
Diabetic glomerulopathy is the leading cause of chronic renal failure in adults. Long-standing type 1 or type 2 diabetes mellitus is associated with this microvascular complication, along with peripheral neuropathy and retinopathy. The pathology of diabetic glomerulopathy is distinguishable based on certain features, including the presence of pathognomonic Kimmelstiel-Wilson nodules, hence the term Kimmelstiel-Wilson disease. A diagnosis of diabetic glomerulopathy does not require a renal biopsy – rather, it is established based on the presence of significant proteinuria and a history of diabetes for >10 years or diabetic retinopathy. Students should be aware about this important complication of diabetes, including its pathology, pathophysiology, clinical course and management.
Patients with the hypoplastic left heart syndrome have a hypoplastic left ventricle, mitral and aortic valves atresia with or without coarctation of the aorta. Blood flow to the systemic circulation is dependent on a patent ductus arteriosus and a patent foramen ovale for adequate mixing of blood in the atria. The diagnosis is confirmed in cyanotic neonates by performing an echocardiography. A three-stage procedure is performed aiming to separate the systemic from the pulmonary circulation. Survival after the completion of the three-stage procedures is as high as 95%.
Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe systemic reaction that is triggered by the introduction of a new drug. Antiepileptics are the most common triggering drugs of DRESS syndrome, followed by minocycline and allopurinol. Patients usually present with a typical skin rash, fever, multiple organ involvement and leukocytosis. Eosinophilia is evident in most cases, but monocytosis can be also seen. The discontinuation of the triggering drug is the only treatment option with a proven impact on the prognosis of the patient. Immunosuppression with corticosteroids and cyclosporine has been also used in the management of DRESS syndrome.
Hemangiomas are considered as the most common tumors in children and they are on the spectrum of benign vascular tumors. They can be diagnosed at birth, but are more likely to become recognized after one month of birth. Hemangiomas undergo a proliferative phase which lasts between one month up to one year and an involution phase which can take years until the complete disappearance of the tumor. They can occur as red or crimson cutaneous lumps, or present with symptoms and signs suggestive of deep organ involvement. Magnetic resonance imaging is essential for the differentiation between the different types of vascular tumors, including hemangiomas. Propranolol is the first-line therapy for problematic hemangiomas. Laser surgery or excisional surgery can be used for treating large and disfiguring hemangiomas.
The right recurrent laryngeal nerve arises from the right vagus nerve at the level of the innominate artery where it loops around the subclavian artery. The nerve then travels along the pleura to the tracheoesophageal groove between the trachea and esophagus. The left recurrent laryngeal nerve has a longer course arising from the left vagus and then loops around the aortic arch and ligamentum arteriosum to ascend parallel to the left tracheoesophageal groove.
Medical genetics involves the application of genetics for the diagnosis and management of hereditary disorders. With the advancement of medical technology, the scope of medical genetics has widened to include the gene interactions, control of gene expressions, gene variations, and environmental interactions. Genetic diseases are now categorized as classical and non-classical. Classical diseases include the chromosomal disorders, Mendelian disorders, and multifactorial disorders. In the non-classical genetic diseases, there is a single gene disorder with an atypical pattern of inheritance. They include the diseases caused by mutations in mitochondrial genes, triplet repeat mutations, genomic imprinting, gonadal mosaicism, and uniparental disomy.
Medical genetics differ from human genetics in that human genetics is a field of scientific research that, or may not, apply to medicine, while medical genetics refers to the application of genetics to medical care.
Nondisjunction connotes the failure of the separation of homologous chromosomes during cell division. It has significant repercussions and is culpable for a large share of chromosomal anomalies like aneuploidy and various hereditary syndromes. With a brief introduction to the basic structure of a chromosome and characteristics of nondisjunction, this article focuses on clinical implications of the same.
Aging is a physiologic process marked by cellular inability to respond adequately to stresses. Epigenetic changes such as reduced histone bulk, abnormal patterns of histone modification as well as abnormalities in DNA formation are some of the causative factors of aging. Another contributory factor to the aging process is the loss of proteostasis which leads to an unstable set of proteins that are toxic to cells and thus trigger the aging process. With the advancement of biomedical science, many new theories have been proposed to decode this mysterious event in a cell’s life.
Serum sickness can happen as a complication to the administration of certain antisera, such as antitoxins, antivenoms, and antibiotics. The condition is characterized by the presence of a rash that is associated with fever, arthritis, and systemic organ involvement. The condition is believed to be immune-complex mediated. Early recognition of the syndrome and adequate treatment have been associated with an excellent clinical outcome. The causative agent should be discontinued and symptomatic treatment is indicated. Immunosuppression with corticosteroids might be needed in more severe cases. Patients who are unresponsive to corticosteroids should be offered plasma exchange therapy.
Psoriasis in children is a chronic inflammatory condition of the skin that is characterized by silvery skin lesions over the extensor surfaces of the elbows and knees in children. On the other hand, seborrheic dermatitis is a chronic skin condition that is characterized by acute exacerbations and is believed to be related to an abnormal immune response to the fungus Malassezia. It is marked by patchy scales formed in sebum rich areas of the scalp, face and trunk in a pattern. Patients with seborrheic dermatitis usually present with dandruff or facial greasy skin lesions. Both conditions are diagnosed based on clinical features in children without any sophisticated laboratory evaluation. Both conditions respond to topical corticosteroids. Topical antifungal therapy has been found to be successful in the management of seborrheic dermatitis in children.
Normal puberty is marked by the maturation of the gonads, breast development in females, and adrenarche, resulting in body odor, acne and pubic and axillary hair growth. Precocious puberty is the development of secondary sexual characteristics before the age of 8 in females and 9 in males. Delayed puberty in males is the lack of testicular enlargement by 14 years old, and a lack of breast development at 13 years old in females.
Several inherited disorders occur as a result of defects in one single gene or due to chromosomal abnormalities; however, some disorders can occur due to defects in several genes and these traits or features can be classified as either multifactorial or polygenic. This article will discuss commonly used terminologies, their definitions, different traits, their risk assessment and examples of multifactorial disorders.
Medium-chain acyl-CoA dehydrogenase deficiency is common among the defects of fatty acid oxidation. Affected individuals present with acute hypoketotic hypoglycemia and mild hyperammonemia. Diagnosis is made through positive newborn screening, and treatment is mainly preventive. Urea cycle disorders are genetic defects. Common symptoms include vomiting, lethargy, seizures, and respiratory alkalosis. Diagnosis is through molecular genetic testing. Treatment aims to reduce ammonia concentration in plasma. Acute episodes can be prevented through a dietary restriction of protein.
Orbital fractures are common in pediatrics and can be isolated or combined with craniofacial fractures. Associated injuries are usually evident and should be excluded in any child who presents with an orbital fracture. A computed tomography scan is usually sufficient in identifying the type of the orbital fracture and in excluding urgent neurological injuries such as intracranial bleeding. Type 1 pure orbital fractures should be treated conservatively, type 2 craniofacial fractures can be treated conservatively, but a vigorous follow-up scheme should be used, and type 3 common pattern fractures are usually treated surgically in children.
Shock in children is a common presentation to the emergency department. Shock can be classified according to the etiology into hypovolemic, cardiogenic, distributive, and obstructive. Hypovolemic shock due to hemorrhage or intravascular fluid losses and septic shock are the most commonly seen types of shock in children. The diagnostic workup and the physical examination of the child should aim to assess the severity of shock and to identify the most probable etiology. Securing the airway and breathing should have priority in the management of shock in children. The circulation should be improved by fluid expansion with fluid replacement therapy or inotropic therapy. Administration of antibiotics in septic shock should be started as early as possible.
Pediatric trauma is common in children and accounts for most of the deaths in children younger than 1 year of age. While head trauma is the leading cause of death in children, most children with significant traumatic injuries have multiple injuries.
Type 2 diabetes mellitus is becoming more recognized in children, especially African American, American Indian and Asian children. Obesity is another very important risk factor for type 2 diabetes mellitus in children. Children with type 2 diabetes usually have a family history of the disease, are obese, have signs suggestive of insulin resistance, and have the typical symptoms of diabetes, such as polyuria and polydipsia. The symptoms, however, are usually of a more insidious onset compared to type 1 diabetes mellitus. Diet, lifestyle modifications and monotherapy with metformin are the main treatment options for type 2 diabetes mellitus in children.
Anxiolytics are a group of drugs that are used to treat anxiety disorders, panic disorders, and generalized anxiety disorder. Anxiolytics can be classified into antidepressant agents, benzodiazepines, and other sedative or hypnotic drugs. The use of a single drug, or a combination, is based on the severity of the symptoms of the patient and the expectations of the patient.
Apnea of prematurity is a condition that is believed to be caused by the immaturity of the respiratory center in the brainstem of premature babies and is characterized by periods of apnea that are longer than 20 seconds. Apnea that is less than 20 seconds but associated with significant bradycardia and/or oxygen desaturation can be also considered as apnea of prematurity. A full diagnostic workup to exclude sepsis, seizures, intracranial hemorrhage and other causes of apnea should be performed. Tactile stimulation is usually sufficient for mild apnea. Oxygen supplementation might be needed in moderate cases of apnea while medical treatment should be provided to severe cases.
Intraabdominal air can be seen on conventional abdominal x-rays, computed tomography scans of the abdomen or ultrasonography imaging. Intraabdominal air can be physiologic or pathologic. The most common cause of normal intraabdominal air is air within the gastrointestinal tract, i.e. the stomach bubble. Pathologic air can be further divided into the extraluminal, intraluminal, intraparenchymal or intramural air. Extraluminal pathologic air can be a pneumoperitoneum or free gas within the retroperitoneum. The most common cause of intramural air is pneumatosis intestinalis.
Congenital infections are common and are associated with significant morbidities for the infant. Classically, congenital infections of the infant have been given the acronym TORCH which stands for toxoplasmosis, others (syphilis, varicella-zoster virus, parvovirus B19 and human immunodeficiency virus), rubella, cytomegalovirus and herpes simplex.
Aging is a complex, mysterious but inevitable end point of a cell’s existence. Numerous theories have been propagated to expound the same; but the unequivocal evidence still eludes us. In this article, after reviewing the basics of aging, we focus on genomic instability and aging.
Aging is an insidiously progressive deterioration in the physiological integrity of a cell resulting in impaired function . With an impetus to biomedical research and advances, it has come accross a multitude of theories expatiated to reason aging. This article focuses on deregulated nutrient sensing and altered intercellular communication and their potential role in diminution of a cell’s vigor, aging and longevity of life.
Toilet training includes training your child to control their bladder and bowels. Girls achieve bladder and bowel control earlier than boys. Enuresis is the voluntary or involuntary voiding of urine during sleep after bladder control is expected to have been achieved. Soiling, also known as encopresis, occurs when the child fails to use the toilet for bowel motions resulting in dirty pants. It is caused by emotional stressor and chronic constipation, resulting in large stool volumes to signal the need to defecate.
Neonatal jaundice is very common in neonates and the decision to treat should be based on the levels of unconjugated bilirubin in the blood. Currently available charts allow for the plotting of serum bilirubin levels starting from the first 24 hours of life and can help the treating physician in deciding whether phototherapy, intravenous immune globulin therapy, or exchange transfusion is needed. The goal of treatment in neonatal jaundice is to prevent kernicterus.
Infants of diabetic mothers are at an increased risk of mortality and morbidity due to the association between different complications and maternal diabetes. The main problems that an infant of a diabetic mother might face include respiratory distress, growth abnormalities and hypoglycemia or hypocalcemia. Additionally, infants of diabetic mothers are at an increased risk of congenital malformations.
Infants are likely to undergo sleep problems especially during the first year of life. Nightmares, night terrors, infant colic, and breath-holding spells are common sleep issues. While nightmares may occur at any age, the night terrors, on the other hand, are typically observed during 3—8 years of life. Approximately, 28% of infants are affected by colic. It leads to intense crying episodes in infants who are 1—6 months old. A breath-holding spell is a non-epileptic disorder of benign nature.
Iron-deficiency anemia (IAD) in children is the most common among other types of anemia. It is commonly presented in children aged between 6 - 36 months than at other age groups, according to a report. Pediatric iron-deficiency anemia might involve multiple etiological factors including low birth weight, nutritional deficiency, and gastrointestinal blood loss. Diagnosis is made on the basis of demonstration of microcytic hypochromic anemia, reduced serum iron, anisocytosis, and poikilocytosis.
Porphyria is a group of disorders that arise from a build-up of chemicals that are involved in the production of porphyrin in the human body. The porphyrins are important as these are essential components of the hemoglobin that carries oxygen to the organs and tissues of the body. When there is a high level of porphyrins in the body, different symptoms or manifestations related to porphyria show.
A femoral neck fracture is associated with high morbidity and mortality. Up to 30% of patients die in the first year following the fracture. It is more common in elderly women. The head and neck are enclosed in the joint capsule within the synovial fluid. No intracapsular callus formation upon fracture, and no periosteal layer which affects the healing process.
Spinal muscular atrophy is an autosomal recessive mutation in the survival motor neuron (SMN) gene responsible for mRNA synthesis and inhibition of apoptosis. The mutation results in a degeneration of anterior horn cells of the spinal cord and motor neurons of the brain stem, leading to lower motor neuron lesions with muscular weakness and atrophy. Both allelic mutations are necessary for the inheritance of the disease phenotype which varies in severity according to both genes SMN1 and SMN2.
Dementia is a syndrome of impairment of cognition and memory accompanied by interference of daily life activities, without a disturbance in consciousness or level of alertness. Dementia should always be differentiated from normal memory loss that occurs with ageing. This change enhanced by old age does not meet the criteria and severity for dementia that limits a person’s physical activity.
Insomnia is a sleep disorder that is marked by difficulty in the initiation, maintenance and consolidation of sleep, giving it poor quality and altered quantity. Symptoms of insomnia are seen in up to 30 % of the population, but only 10 % have severe symptoms that progress to chronic disease. The disease is largely idiopathic but genetic, environmental, social and psychiatric influences have been incriminated. Sometimes, it may be associated with a medical or psychiatric condition (secondary insomnia).
This article provides information test sitters needed for the USMLE Step 2 on the topic of neonatal resuscitation. It provides an overview to the epidemiology of neonatal resuscitation in the delivery room. The article discusses some differential causes of resuscitation need and outlines a procedural overview of resuscitation including initial stabilization, airway breathing and circulation, chest compressions and drug therapy.
Anemia is a medical condition that results from a shortage in the oxygen-carrying capacity of the blood due to a decrease in hemoglobin or number of red blood cells (RBCs). Anemia may be caused by excessive blood loss, inefficient production of RBCs, chronic disease or excessive destruction of RBCs. The type, cause, severity and background health problems are the determinants of the signs and symptoms of anemia. Anemia can be effectively managed through nutritional and medical interventions.
Attention deficit hyperactive disorder is a developmental condition of inattentiveness and easy distractibility with accompanying episodes of hyperactivity. The disease affects about 8–12 % of children in the world, while the worldwide adulthood prevalence is 4–5 %. The disease arises from genetic mutations that may occur due to toxin exposure or hypoxic-ischemic brain injury in the perinatal period. These etiologies cause neurotransmitter deficiencies or structural changes in the brain areas involved in the control of attention and mood.
Tics and related diseases represent a set of neurobehavioral disorders of childhood that are characterized by sudden, repeated, nonrhythmic, muscle movements that are accompanied by sounds or vocalizations. Tourette syndrome is the most severe form with the symptoms running a chronic course of more than one year. The disease is mainly diagnosed by history taking and physical examination of the characteristic tic phenomenon. Treatment involves behavioral therapy, antipsychotics, and treatment of comorbid conditions such as ADHD and OCD. The disease begins in childhood, achieves full expression in adolescence, and disappears in teenage.
Intellectual disability in children refers to a chronic condition of the developmental period involving the limitation in mental functioning and skills such as communication, taking care of oneself and others, etc. Intellectual disability results from any process that either limits the growth of the brain and maturation of cognition or any processes that are toxic to the brain and damage it. These include intrauterine growth restriction, toxin exposure, infections and placental insufficiencies. Perinatal and postnatal factors such as hypoxia, hyperbilirubinemia and infections also cause mental retardation.
Hemolytic–uremic syndrome (HUS) consists of a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal insufficiency (failure), with severity ranging from subclinical to life threatening. HUS, based on etiological agent, can be classified into classic or STEC HUS and atypical HUS. HUS is a common cause of acute renal failure in the pediatric population. In this article, etiology, pathophysiology, clinical features, diagnosis, differential diagnosis, and management of pediatric hemolytic–uremic syndrome are described.
Prenatal screening is used in clinical practice to detect the necessity for carrying out more detailed and invasive tests for the diagnosis of aneuploidies and congenital or developmental birth anomalies. Ideally prenatal screening should be made available to all pregnant women with more invasive testing being offered to those at increased risk. Ultrasonography is an excellent prenatal screening tool while prenatal diagnosis requires invasive tests like chorionic villus sampling, amniocentesis and fetal blood sampling.
Juvenile diabetes is a common chronic disease characterized by hyperglycemia and other metabolic abnormalities. It is more common in children and young adolescents but it occurs in any age. It is a genetic disease with environmental influences that trigger the destruction of pancreatic islet cells. Depletion of insulin levels leads to hyperglycemia, osmotic diuresis, hypovolemia, thirst, and ketoacidosis. Treatment of the disease is by administration of exogenous insulin and supportive care.
Aging is associated with a progressive decline in the functioning of the various organs. Predominant amongst these are hearing and visual loss which contribute indirectly to imbalance and ultimately lead to falls and fractures. Amongst other causes of falls is malnutrition. Most of the diseases in the elderly can be traced to a poor dietary intake, weakness and deficiencies. This article will discuss all these interrelated problems faced by the elderly.
Aging is associated with diseases and decline. Drugs are required to either cure or control these conditions; therefore, older adults end up with a box full of medications for daily consumption which help them to prolong and improve the quality of their life. This, however, increases the likelihood of drug interactions, side-effects of the different medications, mix-ups, compliance problems and drug toxicity. The physician has to be careful when prescribing to the elderly to minimize these issues.
Hypokalemia is defined as plasma potassium less than 3.5mEq/L. Only 1 % of the general population suffers from this disorder with the prevalence rising to 25 % among hospitalized patients. Some risk factors of hypokalemia include elderly patients and people who rely on food poor in potassium content, women and patients recovering from bariatric surgery.
Polycystic kidney disease (PKD) is an inherited genetic disorder leading to the development of numerous fluid-filled cysts in the kidneys. The 2 main types of PKD are autosomal dominant polycystic kidney disease (ADPKD), which is often diagnosed in adulthood, and autosomal recessive polycystic kidney disease (ARPKD), which is often diagnosed antenatally or shortly after birth. ADPKD patients commonly present with hypertension, hematuria, and flank pain. Extrarenal manifestations include intracerebral aneurysm, hepatic and pancreatic cysts, and cardiac valvular abnormalities. Diagnosis is by history, physical exam, and ultrasonography. Management requires a multidisciplinary approach and many patients require renal replacement therapy. The end goal is to slow the progression of renal disease by controlling hypertension, proteinuria, and symptoms. ADPKD prognosis is dependent on a variety of factors. A cerebral aneurysm is a complication associated with a particularly poor prognosis.
Substance abuse is the use of drugs for unintended purposes that harmful to the consumer and/or others. Up to third of adolescents are at risk of substance abuse with a higher risk seen in neglected children, those exposed to drugs by bad influence, poor socio-economic status, and family history of drug addicts. Identification of these children is done by the CRAFFT screening tool or the CAGE questionnaire. Clinical presentation of substance abuse patients can vary based on the type of drug taken. Hyperalertness, restlessness, seizures, dilated pupils, hypertension, arrhythmias, aggressive behavior, paranoia, and tachycardia are commonly seen.
Population genetics is the study of the genetic variation in the population. Using mathematical and statistical models, molecular basis of genetics, Mendel’s laws and modern evolution, population genetics determines how the gene and allele frequency changes over time and the factors which influence it. The study helps to determine populations with a large genetic variation (and therefore more likely to adapt), versus populations with lower genetic variability (and therefore with a lesser possibility of adapting) to environmental changes.
Dizziness, or the feeling of light-headedness or vertigo, is characterised by being in the state of unsteadiness or by having a feeling of whirling sensation. Dizziness can be induced by benign activities including spinning, state of disequilibrium to life-threatening disorders like infections, Dandy’s syndrome, Meniere’s disease, or due to psychiatric origins or due to anxiety. Various signs, symptoms and tests are involved in diagnosing dizziness. Currently, various pharmacological, non-pharmacological and surgical optionsare used for treatment of dizziness.
Colorectal cancer is the third most common cancer affecting the human being. It can be called as polyp-cancer sequence. Colorectal cancer is believed to occur secondary to the transformation of the mucosal epithelial cells characterized by rapid turnover. The mucosal cells protrude into the lumen as polyps which might transform into a dysplastic and invasive lesion. Adenomatous polyps are the most common colon polyps associated with malignant transformation. Herein, we will discuss the different types of colon polyps and genetic basis for colorectal cancer transformation and overview of the management strategies.
Skin lesions have a broad range of etiology and can be complex in diagnosis due to their similar appearance on inspection. Cutaneous T-Cell lymphoma is a rare skin disease that presents with several distinct manifestations. Most common of this manifestation is Mycosis Fungoides and Sezary syndrome. Mycosis fungoides is a slow progressing set of mushroom shaped skin lesions, while Sezary syndrome is a rapidly progressing generalized skin disease with a worse prognosis.
Post-traumatic Stress Disorder is a condition that is usually seen after experiencing a severe traumatic event that threatens the individual’s life or physical integrity. The estimated prevalence of post-traumatic stress disorder in the United States is around 8 - 10%. The diagnosis of the condition is based on the DSM-5 criteria. Laboratory and imaging studies might be performed for research purposes, but are not clinically indicated. Treatment is mainly based upon cognitive behavioral therapy and eye movement desensitization and reprocessing therapy. Beta-blockers or anti-depressants might be indicated in some cases.
Ataxia results from disturbed voluntary muscle coordination, leading to unsteady gait, clumsiness and imbalance. It could be due to neurological or metabolic disease or pseudo ataxia due to weakness, acute illness or anxiety. Neurological causes of ataxia include disorders of the cerebellum, basal ganglia, cerebral cortex or the deep sensation pathway.
Neutrophils are an important component of the immune system and play a significant role in the eradication of infections. Low numbers of circulating neutrophils, referred to as neutropenia, predispose the body to recurrent infections or sepsis, though patients can also be asymptomatic. Most causes of neutropenia are acquired, including neutropenia that is secondary to infections, bone marrow disorders, and/or adverse effects of many drugs. The diagnosis is made using CBC and peripheral blood smears. Management is aimed at preventing and treating infections.
Hypercoagulable states (also referred to as thrombophilias) are a group of hematologic diseases defined by an increased risk of clot formation (i.e., thrombosis) due to either an increase in procoagulants, a decrease in anticoagulants, or a decrease in fibrinolysis. There are both inherited and acquired causes, with factor V Leiden being the most common inherited cause. Clinically, hypercoagulable states present with thrombotic events, which cause vessel occlusion and can lead to organ damage. Thrombotic disorders can be fatal if not treated, and management usually involves anticoagulants.
Hemophilia is a X-linked disorder, inherited in a recessive pattern. Hemophilia A and B are the two main types. The male sex is affected commonly as the disease is transmitted through the X chromosome. Deficiency of the clotting factor VIII and IX is the cause of Hemophilia A and B, respectively. Haemarthrosis is a common symptom, besides a list of other hemorrhagic symptoms. Early investigations and diagnosis is a pre-requisite for an effective treatment.
Nursemaid’s Elbow occurs in children due to weak ligaments. The elbow gets partially dislocated and the child can’t continue the movements through the affected side. There is an associated pain and discomfort. Minor force can cause the condition without any history of trauma or any injury. Diagnosis is made from the history and clinical presentation. The acute cases can be treated with analgesics and closed reduction while the chronic may require an open reduction.
Diabetes insipidus can be caused by central etiologies or by the renal tubular resistance to the effects of vasopressin. Absolute deficiency of vasopressin or vasopressin resistance is associated with renal tubular inability to uptake water and the production of large amounts of diluted urine. Patients become dehydrated and, depending on the severity of dehydration, their symptoms might differ. Treatment of central diabetes insipidus includes desmopressin with or without thiazide diuretics. Nephrogenic diabetes insipidus is treated with a low-solute diet combined with thiazide diuretics and indomethacin or aspirin.
In this article, etiology, pathophysiology, clinical features, diagnosis, differential diagnosis, and treatment of painful testicles in children are described. Acute scrotum is subject to a sudden onset of pain in the scrotum or its contents, accompanied by local signs such as swelling and redness. Many conditions can present with this clinical picture, which explains why this is a diagnostic dilemma. Testicular torsion, in particular, is of major concern because it is a surgical emergency.
Phobic disorders are the most common type of psychiatric illness in the community. Social phobia, specific phobias and agoraphobia are the main types of phobic disorders. The diagnosis of phobic disorders is based on the presence of persistent and exaggerated fear of a certain stimulus that is associated with avoidance behavior of that situation or object and significant impairment in social and occupational functioning. The treatment of phobic disorders includes pharmacotherapy combined with cognitive behavioral therapy.
Mullerian duct anomalies present with developmental malformations of the vagina, cervix, uterus or fallopian tubes. These malformations can involve a single organ or can be a combination. The exact etiology is unknown. The estimated incidence of mullerian duct anomalies range between 2 to 10% based on the studied population. The most common presentation of mullerian duct anomalies is primary amenorrhea. Infertility and cyclic abdominal pain can also be presenting features in patients with these anomalies.
Calcium is an essential mineral. With a pivotal role in bone growth and neuromuscular development, it is of crucial importance in the pediatric population. This article envisages highlighting the significance of calcium homeostasis in children and gives an overview of the pathological states associated with abnormal calcium levels such as hypocalcemia and hypercalcemia.
Postmenopausal bleeding is a uterine bleeding that occurs one year or more after menopause. The inclusion of one year in the definition is very important as menopause and the final menstrual period are both diagnosed retrospectively after one year of amenorrhea. Postmenopausal bleeding is a common problem, and is often caused by endometrial disease. The etiologies of postmenopausal bleeding can be classified into benign and malignant conditions.
Pervasive developmental disorders include autistic disorder, Asperger’s disorder and pervasive developmental disorders not otherwise specified. These disorders are all characterized by chronic and severe impairment across different domains of development that occurs in early childhood. Diagnosis is made with hesitation but rather important for further treatment and the development of the child's behavior.
The perimenopause is a transition period that all women must go through and it marks the final years of the woman’s reproductive years. There are several definitions related to this period that we need to establish before we discuss the pathophysiology behind the different symptoms of perimenopause and the treatment options. The perimenopausal period starts from the first onset of menstrual irregularity and ends after 1 year of amenorrhea. This one year of amenorrhea is preceded by what is known as the final menstrual period; therefore, the final menstrual period is defined retrospectively after the woman develops amenorrhea for one year.
Colorectal cancer is a common malignancy in women which arises from precancerous lesions that undergo a prolonged transition before they evolve into overt carcinoma. The transition from normal mucosa to a precursor lesion to overt cancer occurs over a period of 10–20 years. This understanding of the pathogenesis of colorectal cancer is important as it implies colorectal cancer can be detected and possibly prevented in an early stage, when it is curable. One method of preventing colorectal cancer in women is hormone replacement therapy.
An individual suffering from psychosis loses the contact with reality. A psychotic individual may experience delusions, hallucinations and illusions. Delusions are unshakable false beliefs held by an individual despite being presented with rational and logical arguments and evidence to support the contrary. Hallucinations are deceptions in perceptions that occur in the absence of an external stimulus. Illusions are deceptions in perceptions that occur in the presence of an external stimulus, these perceptions are distorted by the individual's ideas. In this article, we will study in detail about the various types of delusions, hallucinations and illusions.
Hematuria is a common clinical presentation of different conditions in children. Etiology of microscopic and gross hematuria is different. Detailed history, physical examination and focused investigations help identify the cause of hematuria. Management and prognosis are determined by the etiology of hematuria. In this article, etiology, pathophysiology, clinical features, diagnosis, differential diagnosis, and management of pediatric hematuria are described.
Glomerulonephritis (GN) represents a range of disorders of the glomeruli that are immune-mediated. A common histopathological finding is the presence of immune complexes trapped and deposited in the glomeruli. GN usually presents with hypertension, hematuria, proteinuria, and/or renal function deterioration, and complications thereof.
Fractures are a common acute presentation to the emergency departments worldwide. Fractures can be associated with severe long-term morbidity, increased mortality, a huge burden on the healthcare system, and may be intentional or accidental. Abuse, conflicts between people, falls, and motor vehicle accidents are the most common causes of fractures. The number of fractured bones tends to be higher in motor vehicle accidents and falls compared to fractures caused by the other causes.
Fluoroscopy is an imaging technique that employs X-rays to visualize real-time images or videos of the body. The examined organ is made radio-opaque by using some form of dye. In the past, fluoroscopy studies were performed in patients suspected to have structural esophageal or upper gastrointestinal lesions and such structural abnormalities were visualized after a barium swallow. Nowadays, fluoroscopy is reserved for the diagnostic workup of esophageal motility disorders including achalasia and esophageal sphincter diseases such as gastroesophageal reflux disease.
Miscellaneous antiarrhythmic drugs are those whose mechanism of action cannot be attributed to a single class of effect, and every drug inside the group acts by a different class of actions. This group of drugs isn't always the first line of treatment for many conditions, and their use is limited to few specific conditions.
Suicide is one of the leading causes of death worldwide. Patients with chronic medical conditions or psychiatric disorders are at increased risk of suicidal ideation, attempt, and/or completion. The patient assessment of suicide risk is very important as it may help to prevent a serious suicide attempt, which may result in death. Management of a suicidal patient includes medication, psychotherapy, and hospitalization to ensure patient safety.
The main presentation of the different types of arthritis is pain. Pain characteristics, timing, and aggravating or relieving factors can help in the differentiation between degenerative and inflammatory joint disease; however, in this discussion, we will focus on the radiographic differences between the two and the outstanding features of specific types of arthritis.
Breast cancer screening is essential in lowering breast-cancer related mortality and the prevalence of invasive and advanced breast cancer in high risk women. High risk women should receive a screening that is based on at least three imaging modalities, i.e., mammography, magnetic resonance imaging and ultrasonography, for the primary prevention of breast cancer. The use of these three modalities allows for the early detection of breast cancer or precancerous lesions.
Tyrosine is one of the amino acids that play a big role in a number of physiological processes. They are precursors for some hormones and neurotransmitters needed by the body for metabolic functions. In this article, the chemistry of tyrosine will be discussed. The article will answer how it is metabolized to produce the different hormones and neurotransmitters.
Bones constitute the supportive skeleton of the body. They are composed of an organic component of type-1 collagen with calcium, phosphate and hydroxyl ions deposited in hydroxyapatite. Bones are covered with a thin layer of periosteum which provides blood supply to help the healing of bone fractures. Bone fractures are the result of damage to the integrity of normal bones due to direct force or pathological processes.
A mental status examination is a vital tool to the psychiatrist and neurologist in the evaluation of the mental status of the patient. A mental status examination is concerned with the patient’s appearance, attitude, mood, affect, speech, thought process, thought content, insight, judgement, impulsivity, and reliability. It is an objective way of examining how the patient’s mind works and can help in establishing a diagnosis when combined with a proper psychiatric history.
In psychiatry, one needs to be systematic with the approach to the patient so that no less obvious information that might be crucial to the diagnosis is missed. History taking is one of the main tools used by the psychiatrist during their interview with the patient suspected to have a mental disorder.
The Mullerian ducts are the human anlage of the female reproductive tract. They differentiate to form fallopian tubes, uterus, uterine cervix and the superior aspect of the vagina. Congenital uterine anomalies, also known as Mullerian duct malformations, are quite common in women. Approximately 0.001 to 10% of women are diagnosed with a congenital uterine anomaly depending on the studied population and the method used. Most identified anomalies of the female reproductive tract are found within the uterus. Isolated cervical, vaginal or fallopian tube defects are much rarer compared to uterine anomalies.
Abdominal CT scan is an excellent way to visualize the contents of abdomen. Use of specific X-ray machine for capture images of inside of abdomen is the feature of abdominal CT scan. It provides detailed images of abdominal organs such as liver, pancreas, spleen, kidneys, gastrointestinal tract, colon and rectum. These images reveal more detail information than typical X-rays. Cross sectional images of abdominal contents can be obtained through CT scan. With the introduction of contrast during abdominal CT scan, many relevant structures of abdomen can be highlighted and observed for definite diagnosis of abdominal pathology.
Ultrasonography is an imaging technique used in medicine for the imaging of subcutaneous body structures, blood vessels, joints, and internal organs to exclude structural pathologies. This technique is based on the utilization of ultrasound (or high-frequency, inaudible sound waves). In medical imaging, the sound waves have a frequency of 2–18 megahertz (MHz). The equipment utilizes a transducer acting as the emitter and receptor of sound waves, and a central computer processes the electrical signals to generate the image. The general advantages of this type of imaging is its low cost, availability, and safety. Some specialties that rely heavily on ultrasound examination are cardiology, nephrology, general surgery, gastroenterology, emergency medicine, and obstetrics.
Ovarian tumors are the leading cause of cancer-related deaths in gynecological malignancies. Additionally, they are the fourth leading cause of death related to cancer. Ovarian tumors can be epithelial, germ cell, sex cord stromal or metastatic. Germ cell tumors are the most common type of ovarian tumors in children. Young adults with ovarian tumors can have an epithelial, germ cell or a stromal tumor with equal probability. Middle-aged women and the elderly who develop ovarian tumors usually have an epithelial ovarian cancer.
Hirsutism is defined as excessive growth of terminal hair in females in an androgenic manner, whereas virilization refers to elevated androgen levels leading to male physical characteristics in addition to hirsutism. In this article, etiology, clinical features, diagnosis, differential diagnosis, and treatment of hirsutism are described.
Cellular senescence is the cessation of theprocess of division of the cells. Aging is an insidious definite decline in a cell’s functionality, vigor, and vitality. Recent advances in biomedical research, cytogenetic and molecular studies have brought forth fascinating theories to expatriate aging and, more importantly, to tame aging to modulation by genetic and pharmacological manipulations. This article focuses on the effect of cellular senescence and stem cell exhaustion on aging and the subsequent clinical implications.
The spleen is the largest ductless gland and largest single lymphatic organ in the human body. The main functions of the spleen are immunologic surveillance, red blood cell breakdown and splenic contraction for blood volume augmentation during hemorrhagic shock. The most common splenic abnormalities are congenital anomalies of the spleen, traumatic injuries, inflammation, vascular disease related changes, hematologic disease-related changes, benign splenic lesions and malignant splenic lesions.
Abdominal calcifications are generated by a wide range of normal and pathological factors. The prominent symptom of abdominal calcification is the pain experienced by the patient. Abdominal calcifications are categorized into four groups according to their morphology, i.e. concretions, conduit calcification, cystic calcification, and solid mass calcification. The anatomical location of the calcification aids in establishment of a reasonable differential and definite diagnosis. This categorization and location of calcification should be accompanied by radiology to facilitate effective management.
Traumatic injuries to the spine or the spinal cord might cause severe neurological deficits or even death. The mechanisms of injury that can cause spinal or spinal cord trauma usually cause injuries to multiple other organ systems and are associated with polytrauma. The most commonly injured part of the spine is the cervical spine. Half of the cases involve fractures within the cervical spine; the remainder of the cases are distributed between thoracic, lumbar and sacral spinal injuries.
The most common cause of death in the pediatric population is unintentional injury. Approximately 20,000 children each year become disabled because of trauma, and 15 million children per year visit the emergency department because of unintentional injuries. The incidence of musculoskeletal injuries in children is around 1068 cases per 10,000.
The diagnosis and identification of the etiology of lower abdominal or pelvic pain in a pregnant woman can be challenging. Routine blood workup for acute abdomen in pregnant women is challenging due to physiologic alterations induced by normal pregnancy. Additionally, the anatomic location of the different pelvic organs can be altered by the growing uterus. Thus, it has become clear that sophisticated imaging modalities in pregnancy are needed for the diagnosis of acute abdomen, and such imaging modalities should prove to be harmless to the mother and the growing fetus.
The intrahepatic biliary system can be injured in blunt abdominal trauma, in an inflammatory process, such as biliary sclerosing cholangitis, or can be involved in some benign and malignant neoplasms. The radiographic evaluation of the intrahepatic biliary system mainly consists of computed tomography, ultrasonography, and magnetic resonance cholangiography with hepatobiliary contrast and hepatobiliary scintigraphy. The main goal of each imaging modality in each disease process is different. In this article, we will discuss three main biliary pathologies: traumatic biliary leaks, intrahepatic biliary adenoma and intrahepatic cholangiocarcinoma.
Trauma is the fourth leading cause of death and morbidity in the United States. Blunt abdominal trauma is more common than penetrating injuries. The most commonly injured intra-abdominal organ is the spleen, followed by the liver and the genitourinary tract. After careful clinical examination and primary survey, imaging should be used to exclude life-threatening injuries such as rupture of a major blood vessel.
Today, forensic psychiatry is a broader science that entails the study of the interaction of psychiatry and the law. It entails matters of criminal law, civil law and development and application of mental health legislation. In most situations, a third-party requests forensic psychiatry help; say a policeman may divert a mentally ill person to the hospital emergency department for treatment if needed. The main entities of forensic psychiatry include: informed consent, competence and capacity, criminal matters, and malpractice in psychiatry.
Impulse control disorders are characterized by an uncontrollable and irresistible urge to do certain activities that lead to harm to oneself and others. They mainly include compulsive gambling disorder, kleptomania, pyromania, and trichotillomania/hair pulling. The disorders have a low prevalence of 0.5% to 10%. The pathogenesis of the disease involves deranged levels of neurotransmitters, such as dopamine and norepinephrine.
Neuroleptic malignant syndrome is a rare, idiosyncratic, and potentially life-threatening reaction to a neuroleptic (i.e. antipsychotic) drug, although other drugs can also trigger it. Although the exact cause is uncertain, one of the main mechanisms seems to be a sudden deficiency of dopamine in the central nervous system. It is important to promptly identify this condition because of high morbidity and mortality. In this article, epidemiology, etiology, pathophysiology, diagnosis, differential diagnoses, treatment and prognosis of neuroleptic malignant syndrome are described.
Several benign or malignant lesions can affect the adrenal glands. These abnormalities include benign adenomas, other benign tumors, malignant tumors, hemorrhage, metastasis and adrenal gland hyperplasia. The finding of an adrenal gland lesion might be incidental in many cases, i.e., an incidental adrenal adenoma on an abdominal computed tomography scan ordered for an unrelated issue. The diagnosis of a mass as an ‘adrenal incidentaloma’ has become increasingly problematic leading to a shift in terminology by radiologists. Thus, modern day adrenal masses are only classified as benign, malignant or indeterminate depending on various features. Most adrenal lesions are benign adenomas. However, malignancy must be ruled out via various imaging modalities such as CT scan, PET scan and MRI.
An impulse control disorder is a psychiatric condition characterized by a person's inability to resist an impulsive action or behavior that can turn out to be harmful to them or others. Usually, people suffering from impulse control disorder experience a feeling of increased anxiety prior to committing the action due to pressure building up. Once the deed is done, they feel relief or even happiness, in spite of the possibly dangerous consequences. This psychiatric condition is mostly misunderstood by the general public, clinicians and even the individuals suffering from it.
Intermittent explosive disorder (IED) is an impulse-control disorder, characterized mostly by abrupt episodes of unnecessary fury or impatience. The disorder is signified by violence, impulsiveness and persistent aggressive outbreaks. These erratic and explosive outbursts can cause significant distress in the person, have a negative impact on their relationships, work and school, and they can also have legal and financial penalties. There are many symptoms and these are mostly based on individual genetics, presence of co-occurring complaints and habit or addiction to drugs or alcohol.
Pleural thickening, diffuse pleural thickening (DPT), is a result of a severe inflammation of the pleural sheets, a thin membrane that covers the lungs, leading to the consolidation of the tissue due to a specific scaring. One of the causes for the condition is empyema that develops when pus builds-up in the space between the lung tissue and pleural space (the inner surface of the chest wall). With the advance of the scaring, the lungs may be encapsulated with the thick tissue, with the further disappearance of the natural space between the pleural cover and the lungs. The after-effect of this condition is a reduction of total lung capacity (TLC), thus, the deterioration of respiratory function and hemodynamic disorders due to growing hypoxemia.
The alteration of the lung volume, in the form of reduction of total lung capacity (TLC), is regarded to restrictive lung diseases; as a rule the diseases of the chest wall and muscles, neuromuscular apparatus stipulate it; also, there are parenchymal ailments that may adjust the respiratory function of the lungs. The former ones lead to the decrease of TLC and refer to extrapulmonary diseases, and vice versa, the latter ones cause elevated TLC, like in COPD and asthma.
People with mood disorders, anxiety disorders, specific phobias, obsessive-compulsive disorder, or thought disorders often need psychotherapy in addition to their medication. Psychotherapy is defined as the systematic interaction between an individual and a therapist that is based on the understanding of the psychological principles and mechanisms of mental disease with aim of changing the individual’s behaviors, thoughts and feelings. Therefore, the optimum goal of psychotherapy is to help the patient to overcome certain abnormal behaviors such as being frightened from a stimulus, solve their daily-life problems and help them achieve their potential.
Formal thought disorder, or disorganized thinking, refers to a disturbance in the coherence of a person’s oral communication. There are many types ranging from low content of speech to excessive tendency to go off topic to coining new words or using existing ones in a highly unusual way. Formal thought disorder is particularly associated with the psychotic spectrum of diseases (typically, schizophrenia), but some types can be seen in some mood disorders as well as non-psychiatric etiologies. It may be accompanied by delusions and/or hallucinations, which are useful in narrowing down a diagnosis. In this article, common types of thought disorders, its epidemiology, etiopathology, diagnosis, and treatment will be discussed.
The chest X-ray is a cheap, feasible, screening tool for cardiac and respiratory diseases in neonates, children, and adults. The heart shadow on the chest X-ray “cardiac silhouette” occupies half of the anteroposterior chest X-ray film in normal individuals. Therefore, the examination and evaluation of the cardiac silhouette on the conventional X-ray has received interest from radiologists and pediatricians. The main aim of examining the cardiac silhouette is to determine the heart’s size, the identification of the different contours of the heart, and the categorization of the pulmonary vascularity.
Mycoplasma pneumoniae is a common cause of lower respiratory tract infections in adults and children. Up to 40% of the cases of community-acquired pneumonia are caused by mycoplasma pneumoniae. The diagnosis of mycoplasma pneumoniae pneumonia is based on the clinical manifestations, radiographic findings, and serology testing. Because of the good response to macrolides and the favorable natural history of the infection, advanced polymerase chain reaction testing for the confirmation of the disease is rarely needed.
Children are a unique group in that they are at an increased risk of falling and lacerate themselves. Up to two thirds of bite wounds that present to the emergency department are found in children. Playing with other peers, or even fighting with each other can end up in getting bitten. Whether the mechanism of injury is fall or bites, the local care of the laceration is quite the same.
Juvenile idiopathic arthritis is a chronic inflammatory condition that occurs in children and is characterized by the involvement of a single joint (psoriatic type), 1-4 joints (oligoarticular), 5 or more joints (polyarticular), or systemic-onset disease. The exact etiology is unknown, but genetic predisposition is likely to play a significant role in the pathogenesis. The diagnosis is based on clinical criteria which can be supported by laboratory findings. Treatment is dependent on the exact type of the disease and mainly consists of non-steroidal anti-inflammatory drugs, steroids, methotrexate and tumor necrosis factor alpha inhibitor. Biologic disease-modifying antirheumatic drugs have recently been approved for use in juvenile idiopathic arthritis.
Cognitive disorders are characterized by disruption of, or deficit in learning, memory, perception and problem-solving. There are four major kinds of cognitive disorders: delirium, dementia, amnesia and cognitive disorders due to general medical condition or substance use. In this article, an overview of cognitive disorders and tests performed to assess cognitive function will be discussed.
Prolactinomas are benign hormone-secreting pituitary tumors. They can cause symptoms secondary to prolactin secretion as well as space-occupying lesion effects. The management of prolactinomas in pregnancy differs from the non-pregnant state. In this article, etiology, pathophysiology, epidemiology, symptoms, diagnosis, differential diagnosis, management, and treatment of prolactinomas in males, pregnant and non-pregnant women are described.
Transient Synovitis is an acute inflammatory condition that involves the hip. It is considered as the most common cause of hip pain in children and is usually a self-limited disease that does not need any specific treatment. The main goal of the diagnostic workup for transient synovitis is to exclude septic arthritis (a bacterial or fungal infection that results in joint inflammation and can lead to permanent joint damage if left untreated), another cause of single joint arthritis that can cause severe joint damage.
Granulomatosis with Polyangiitis (GPA) and Goodpasture's syndrome are two similar conditions that are characterized by small vessel disease and are considered autoimmune conditions. Goodpasture's disease, on the other hand, is a different condition from GPA and is characterized by glomerulonephritis with anti-glomerular basement membrane antibodies. Both conditions are rare in children. The prognosis of GPA and Goodpasture's disease has improved dramatically in the last few decades; however, mortality remains high. GPA and Goodpasture’s disease present with fever, hemoptysis, shortness of breath, and symptom and signs suggestive of kidney disease.
Mediastinal masses can be benign cysts, neurogenic tumors, germ cell neoplasms, thymomas or lymphomas. The mediastinum is demarcated by the pleural cavities laterally. Superior to the mediastinum, you find the thoracic inlet. The mediastinum is usually divided into three main compartments: anterior, middle and posterior. This anatomical classification of the mediastinum is useful for the radiologist as the differential diagnoses of a mediastinal mass is dependent on the anatomical location of the mass—among other factors.
Headache is common in both adults and children. Children of all age group report having some sort of acute and chronic attacks of headache. In children, it can be classified into primary or secondary to another cause. Primary headaches are similar to the adult group including migraine which is the most common, cluster headache and tension-type headache. Secondary headaches are caused by another lesion; infection, CNS tumors, hydrocephalus, cerebrovascular lesions, and trauma. The most common secondary headache is due to acute viral illness or respiratory infection.
Sometimes, in surgical wards and at the emergency department, the radiologist might see a chest x-ray with a complete white-out of a hemithorax. The number of causes that can cause a complete white-out of a hemithorax on a chest plain radiography is limited. To better understand such causes, we chose to classify them according to the position of the trachea.
Child sexual abuse is a broad term that includes many acts that can be sexually abusive toward children. The most common acts covered in the loosest definition of child sexual abuse are sexual assault, rape, incest and sexual exploitation of children for commercial and financial reasons. Child sexual abuse can be considered as completed or non-completed (attempted).
Hemoglobin is the iron-containing metalloprotein that is responsible for oxygen transport in vertebrates. It is present in the blood and functions mainly to carry oxygen from the lungs to the other parts of the body, and carbon dioxide from the body to the lungs for eventual elimination. This article will focus on the basic structure and function of hemoglobin.
Many of the symptoms and signs of menopause can be attributed to the cessation of the production of estrogen by the ovaries in the menopausal stage. The most common complications that women face during menopause include vaginal dryness, soreness, dyspareunia, urinary frequency and urgency. Mood changes are also common during menopause and in postmenopausal women. Vasomotor instability can cause hot flushes, sweating and palpitations in menopausal women.
This article should provide an overview of the main type of diseases that affect the lung. You will find a description of the important diagnostic tests used for investigating respiratory diseases, like general principles, emphasis on lung function testing role and interpretation and examples of diagnostic testing approach for some common presentations.
The incidence of pancreatitis in the pediatric population has been on the rise recently. It has a grave impact on the quality of life when present from a young age. This article expounds the basics of pediatric pancreatitis, while focusing on the clinicopathological aspects of pancreatitis.
This article deals with the normal sexual development in humans. It defines the various terms used to describe gender and sex, from genetic to phenotypic sex. The genetics behind sex determination is shortly dealt with, as well as the development of the internal and external genitalia in embryonic and fetal life. The differentiation of the mesonephric and paramesonephric ducts is briefly described, and we end with a short summary of sex determination in the male and the female.
Disruptive behaviour disorders are impaired patterns of behaviour, occurring in children and adolescents. The two types are conduct disorder and oppositional defiant disorder. In this article, epidemiology, etiology, sign and symptoms, diagnosis, and treatment of disruptive behaviour disorders will be discussed.
When there is a conflict between a person’s subjective moral sense and the person’s thought, feeling, or action, the ego uses defense mechanisms to keep them away from conscious awareness. These subconscious defense mechanisms serve to protect the self from unpleasant feelings, which often including anxiety, shame, and/or guilt. Although these are normal occurrences, used in excess, they can hinder insight or treatment compliance.
Chronic pelvic pain (CPP) is a frequently occurring disorder in women and its etiology cannot always be determined. The pain could be in the urogenital tract, gastrointestinal tract, musculoskeletal or psychoneurological in origin. The common gynecologic causes of CPP are endometriosis, adhesions and interstitial cystitis. Diagnosis is based on a detailed history, thorough physical examination, laboratory and imaging studies and laparoscopy. Treatment could be symptomatic as well as specific treatment of the gynecologic disorder.
Physicians, especially family physicians, are often the first contacts for survivors of intimate partner violence and occasionally for sexual assault victims too. Both these problems are prevalent worldwide with both sexes being affected, although women are more affected than men. Besides physical harm and death, intimate partner violence (IPV) and sexual assault can also cause psychological and psychiatric problems. Family physicians should be prepared to identify and provide supportive care to these patients.
The pituitary gland/hypophysis is in the Sella turcica/pituitary fossa which is a part of the sphenoid bone and forms the cranial fossa. The gland is divided into the posterior and the anterior pituitary. The most common cause of these disorders is pituitary tumors which are mostly benign (Adenomas) in nature. Diagnosis in most cases is made with MRI, CT imaging and laboratory work-ups. Treatment approaches for pituitary gland disorders involve various methods including medication and surgery. Prognosis depends on the diagnosis.
Hematopoiesis is the process of blood cell formation. It begins in embryogenesis and progresses to adulthood to replenish the cellular component of blood. The sites of hematopoiesis include the yolk sac at the embryological age of 0 - 2 months and
the liver and spleen during the embryological age of 2 - 7 months.
The bone marrow and thymus are definitive sites of hematopoiesis that take over the function from 8 months to adulthood.
Extramedullary hematopoiesis in the spleen and liver can either the bone marrow is destroyed and cannot fulfill the function anymore.
Rotator cuff injuries can occur in older and younger adults. These injuries can range from tendinitis to complete tears of one of the rotator cuff tendons and muscles. Rotator cuff injuries can occur due to repetitive overhead activities, direct trauma to the shoulder, or senile degeneration of the tendons of the rotator cuff. Magnetic resonance imaging is the most accurate imaging modality for the visualization of the rotator cuff muscles. The goal of the management plan is to make the patient independent, and completely pain-free with a full range of motion, and surgical treatment as the last option.
Paraneoplastic syndromes are rare disorders caused by a change in immune system response to a neoplasm. It is a disorder that produce a nonmetastic impact on systemic organs due to production of substances by the remote tumor cells in the body.
Carcinogenesis, also known as tumorigenesis which stands for the process of transforming a normal cell into a cancerous cell. Strictly defined carcinogenesis represents the initiation of a tumor-forming process, while oncogenesis represents maintenance of the tumorous state in cells that have already changed into a cancerous state. The process is largely dependent on the imbalance between proliferation and programmed cell death (apoptosis) in the cell division pattern.
Attention Deficit Hyperactivity Disorder (ADHD) is a developmental condition of inattentiveness and easy distractibility with accompanying episodes of hyperactivity. The disease is common in children but also occurs in adults, with a prevalence of 4.4% in the United States and 3.4% worldwide. The disease is supposed to arise due to neurotransmitter deficiencies or brain structural changes resulting from genetic mutations or hypoxic-ischemic brain injury in the perinatal period.
Hyperemesis gravidarum is defined as severe, persistent nausea and vomiting during pregnancy leading to dehydration, electrolyte imbalance, ketosis, loss of more than 5% pre-pregnancy weight and can even result in mortality.
These are kidney diseases that involve structures outside the glomerulus. The causative agents incite a hypersensitivity reaction that leads to an inflammatory infiltrate seeding into the kidneys interstitium and irreversible features of fibrosis and sclerosis. This leads to the diseases presenting as an acute kidney injury that may end up as an end stage renal disease. Management is per the acute renal injury algorithms that advocate for identification of the inciting agent and its discontinuation alongside watching out for end stage renal disease and timely institution of renal replacement therapy.
The selection of contraceptives is a personal choice, but the physician should provide information to the patient regarding the optimal contraception. The postpartum period is an ideal time to initiate contraception as women are continuing to follow up with their healthcare providers and are likely to be more motivated to avoid the next pregnancy soon. Postpartum contraception should consider factors like a resumption of ovulation, its effects on lactation, and the woman’s health. Ideally, all women requesting postpartum contraception should be advised not to wait until the resumption of their menstrual cycle but instead start their contraceptive use before resuming sexual activity. Physicians should also provide emergency contraception, if requested, to all women.
An incongruous alteration in the flow of blood in the form of steal syndromes is a well-known complication of coronary artery bypass grafting (CABG). It might be discovered incidentally, that is during an ultrasonographic or angiographic examination performed for any other indications, or during the clinical examination, finding of reduced blood pressure or unilateral upper-limb pulse. Treatment mostly comprises of open subclavian artery revascularization, normally via carotid-subclavian bypass or subclavian artery transposition, and new less invasive options which are endovascular intervention with recanalization, angioplasty with stenting if needed.
The urinary system consists of the kidneys, ureters, urinary bladder, prostate, and testes; however, the collective term urologic cancers usually refer to the carcinoma of the urinary bladder and the prostate. The urinary bladder is a hollow organ that is used to store urine before its excretion. When urine is produced from the kidneys, it is supposed to go down the ureters and to reach the urinary bladder via the two ureter orifices. The urinary bladder is composed of an inner layer that is lined with urothelial and mucosal cells, a lamina propria layer that is mainly connective tissue, and a third layer that contains smooth muscle.
Pleural effusions are a common encounter at the emergency department, outpatient and inpatient wards in hospitals. Up to one-half of the hospitalized patients with bacterial pneumonia are expected to develop or have pleural effusion during their admission. Moreover, up to two-thirds of intensive care unit patients are found to have a pleural effusion for one reason or another.
Proximal tubule is divided into proximal convoluted tubule (PCT) and proximal straight tubule (PST). The proximal convoluted tubule is the convoluted portion of the nephron that extends between the Bowman’s capsule and the loop of Henle. Its main function is to reabsorb salt and water, organic solutes like sugar and amino acids, potassium, urea, and phosphate. It also secretes ammonium in the urine.
In this article, you will learn more about thermodynamics and thermochemistry in order to be best prepared for your exam. You will increase your knowledge about Hess´s Law, Gibb´s Free Energy and the coefficient of thermal expansion.
CNS tumors in pediatrics are rare but account for approximately 20 % of cancers in children. Most patients with CNS tumors have supratentorial brain tumors. Patients usually present with headaches, focal neurological deficits with or without seizures. Brain imaging is essential in the diagnosticworkup and a histological examination should be performed on an excisional or incisional biopsy. The histological classification of the tumor has an impact on the decision to offer adjunctive chemotherapy or radiotherapy after surgical resection.
Wiskott-Aldrich syndrome (WAS), also known as eczema-thrombocytopenia-immunodeficiency syndrome, IMD2, or immunodeficiency 2, is a rare genetic mixed disorder of B- and T-cell deficiency that follows an X-linked recessive inheritance pattern. It is caused by a WAS gene mutation that leads to impaired actin cytoskeleton, phagocytosis and chemotaxis, impaired platelet development, and, in general, a loss of humoral and cellular responses.
Wiskott-Aldrich syndrome presents as a classic triad of eczema, bleeding diathesis, and recurrent opportunistic infections, but also carries a high risk of development of autoimmunity and malignancy. Management includes hematopoietic stem cell transplantation (HSCT), immunoglobulin replacement therapy, prophylactic and therapeutic antibiotics, and systemic steroids. Without HSCT, prognosis is poor and life expectancy is shortened.
Lipid is one of the biomolecules important to humans. They serve a number of purposes in human metabolism. In the absence of carbohydrates, acetyl CoA does not enter the TCA cycle, instead, are processed to form ketone bodies, cholesterol, steroid hormones, and bile acids. This article focuses on the metabolism of these four compounds.
Patients living in remote areas or those with limited access to the hospital care system typically present first to the primary health care physician if they sustain a traumatic injury to the eye. Therefore, it is essential for the general practitioner to have a general idea about the several types of acute ocular emergencies and to be able to manage them properly at the primary care level. The primary health care physician needs to make two important decisions in case of an ocular emergency: should the patient be referred to the emergency department at the hospital? And, if yes, how and when should the referral be made?
The human immunodeficiency virus (HIV) is a retrovirus that can be transmitted vertically, sexually or via blood products. Intravenous drug use has been also associated with HIV infection. The main mode of transmission of HIV in children is vertical transmission during pregnancy, delivery or after birth. The estimated risk of perinatal transmission of HIV from the mother to the baby is around 40% if the mother does not receive any treatment. Perinatal transmission is responsible for 80% of pediatric HIV cases. Sexual abuse of children and adolescents is also a risk factor for HIV infection.
Patellofemoral pain syndrome (PFPS) is a common condition that is characterized by anterior knee pain. The condition is more commonly seen in young women. Patellofemoral pain syndrome is characterized by the absence of any significant structural changes and with a normal articular cartilage. PFPS is a diagnosis of exclusion.
Chest pain is a common and challenging presentation to the outpatient family medicine clinic. When a patient with chest pain is encountered, the main goal of your evaluation is to exclude life-threatening causes. Once life-threatening causes of chest pain are dismissed, the categorization of the patient into cardiac and non-cardiac chest pain is helpful.
Breast cancer is the most common cancer in women affecting 1 in 8 women in the united states. Up to 40% of female cancer survivors belong to this group. The early detection of breast cancer, along with pathology-specific treatments resulted in a 5-year survival rate that is above 90%; therefore, it became clear for the American Society of Clinical Oncology (ASCO) that a guideline mainly focusing on the care of breast cancer survivors is needed.
Premenstrual syndrome is a vague term that is used to describe a wide range of symptoms severity that are confined to the luteal phase of the menstrual cycle and that recur in multiple ovulatory cycles. These symptoms should cause significant impairment in the quality of life.
Knee pain is a common encounter in the general practitioner’s office. Up to one third of musculoskeletal problems seen in primary care are related to knee pain which can be acute or chronic. Knee pain is more common in active people such as athletes. Half of athletes complain of acute knee pain per year. Trauma, osteoarthritis, rheumatoid arthritis, and gout are the most common causes of acute knee pain.
Antidepressants are commonly used by women in child-bearing age. When antidepressants are used, they can influence the fetus in one of four ways. Antidepressants might be associated with an increased risk of miscarriage, teratogenesis, neonatal toxicity, or long-term neurobehavioral sequelae. As we shall explain later, most commonly used antidepressants were not found to be associated with an increased risk of miscarriage. Omphaloceles, gastroschisis, anencephaly, and craniosynostosis might be slightly more common in the offspring of women taking antidepressants.
Cryptococcosis is a fungal infection caused by Cryptococcus neoformans and Cryptococcus gandii. The encapsulated organisms are inhaled and survive in the respiratory tract without causing any harm. However, depending upon the immunity of the individual, it may result in several clinical diseases. Cryptococcosis is therefore known as an opportunistic infection. Patients with immune deficiency such as HIV, corticosteroid therapy or reticulo-endothelial malignancy may suffer from the additional debilitating effects of the disease.
Patent ductus arteriosus is a common congenital heart disease that can bepresent isolated but is usually present with other co-existing congenital heart anomalies. Patients usually have a previous history of hypoxia, or premature baby or have a maternal history of rubella infection. Echocardiography is the diagnostic modality of choice for the confirmation of the diagnosis. The administration of indomethacin can stimulate the closure of the patent ductus arteriosus. Surgical treatment should be reserved for highly symptomatic patients with a large patent ductus arteriosus.
Lipids are a large and diverse group of naturally occurring organic compounds that have relatively very low solubility in water and higher solubility in non-polar organic solvents. Different types of lipid molecules include fatty acids, fats, oils, waxes, phospholipids, eicosanoids, steroids etc. The focus of this article is on two types of lipids, namely glycerophospholipids and sphingolipids. Specifically, the article emphasizes on the synthesis of these two types of lipids.
Contraception refers to the process/methods that allow one to have children by choice other than by chance. These methods can be based on certain behaviors, physical barriers, chemical compounds, or hormonal therapies.
Cholesterol (Greek for: ‘gall’ and ‘solid’) is a media star: For decades, no other biochemical substrate draws as much attention as cholesterol has. But what are the hard pre-clinical facts? How is cholesterol synthesized and degraded in the human body? How is cholesterol metabolism regulated? The following article presents you with useful information that will aid you in your exam preparation.
The postpartum (PP) period is a common time for the emergence or exacerbation of psychiatric disorders. Postpartum blues, PP depression, and PP psychosis are 3 of the most common psychiatric disorders experienced in the PP period. Although both genders are affected, PP is more common in women. Postpartum blues and PP depression affect up to 80% and 25% of women, respectively. Postpartum psychosis is less common but can be more serious. Unfortunately, perinatal mental illness is largely underdiagnosed and undertreated. Diagnosis is clinical, and management typically involves psychotherapy and antidepressants. Antipsychotics are used in the management of PP psychosis.
Ageing is a genetic but environmentally modulated process that one becomes older. There are various theories hypothesized to elucidate aging, such as loss of telomere length (telomere attrition), increase in p13 expression and mitochondrial dysfunction which arises from errors in replication and mutations. The three pathways culminate into accumulation of reactive oxygen species and onset of age related diseases such as cancer and degenerative diseases.
Brain herniation is a potentially fatal condition that may present as a rise in intracranial pressure. The following text describes the various clinical signs to recognize this condition and the possible measures one can take to treat it.
Vitamins are the organic compounds which are required in small quantities for normal growth, reproduction and maintenance of the human body. They are different from other organic food stuff because they do not go through the degradation processes to provide energy, and do not enter the tissue structure. Moreover, several B vitamins act as a coenzyme in various metabolic reactions of the body. Vitamins are also different from hormones as they are not produced by the body and have to be taken through diet. They are classified on the basis of their biological and chemical activity.
With the advancement of age, older adults go through changes that have an impact on their nutrition. Changes can be physical, psychological, health-related or social. Their extent varies among different individuals. Senior citizens can enjoy a quality of life despite these changes, given that they are healthy. Malnutrition is a result of not getting adequate caloric intake and nutrients. Older people are at a greater risk of developing malnutrition. Moreover, if this is combined with disease, it would lead to the spiral of dependence and hospitalization.
One of the most common reasons for the death of almost 300,000 children per year is malnutrition. It is seen more frequently among children who are younger than five years and reside in the developing countries. The number contributes to half of the total deaths in the child age groups across the world.
Protein-energy malnutrition (PEM) is a type of malnutrition commonly seen among children aged six months to 5 years.
Chronic granulomatous disease is caused by impaired phagocyte NADPH oxidase complex activity, or complete absence of the enzyme. X-linked and autosomal recessive patterns of inheritance have been described for the condition. Patients usually present with recurrent skin, lung and gastrointestinal infections. Granulomas can form in the skin, gastrointestinal tract or genitourinary tract. Patients should undergo qualitative and quantitative testing of the oxidase complex enzyme from isolated neutrophils. The mainstay treatment of chronic granulomatous disease is antimicrobial therapy and interferon-gamma. Hematopoietic stem cell transplantation is curative, but carries significant risks.
Medulloblastomas, primitive neuroectodermal tumors and ependymomas constitute a significant number of central nervous system tumors in children. Medulloblastomas and PNETs are more likely to have been metastasized at the time of diagnosis, compared to ependymomas. The clinical presentation of medulloblastomas and ependymomas is usually due to increased intracranial pressure, while PNETs usually present with head and neck masses. Surgical resection of the tumors is the mainstay of treatment which should be followed by radiotherapy in most cases. Chemotherapy in medulloblastoma and PNET has a proven effect on survival, but its role in ependymomas is still unknown.
Infective endocarditis is a common serious infectious pathology in children. The most commonly identified organisms are of the streptococcus and staphylococcus species. Patients always have a fever. Other signs of infective endocarditis include Roth spots, splinter hemorrhages and Osler nodes. Blood cultures and echocardiography are very important in the establishment of the diagnosis. The diagnosis of infective endocarditis is based on the presence of major and/or minor criteria from the modified Duke’s criteria for infective endocarditis. Antibiotic therapy is essential and life-saving.
CVID, also known as humoral immunodeficiency, is characterized by reduced serum levels of immunoglobulins G and A and, in some patients, also immunoglobulin M. Patients present with recurrent infections, an increased risk of autoimmune disorders and malignant disease. Quantification of serum levels of immunoglobulins, in addition to assessment of the functional activity of lymphocytes, is indicated in the diagnostic workup of CVID. Specific culture and sensitivity tests should be performed in patients with infectious complications to guide antibiotic therapy. Treatment of CVID includes antimicrobial therapy, immunoglobulin replacement therapy and immunomodulation therapy in patients with autoimmune disease.
Pediatric lymphomas are rare compared to other malignancies in children. They can be classified into Hodgkin's and non-Hodgkin's lymphomas. Hodgkin's lymphoma is more likely to present with systemic features such as fever, weight loss and night sweats. Non-Hodgkin's lymphoma is more likely to present with primary extranodal involvement. Histologic examination is essential in both conditions to confirm the diagnosis. Staging of the disease is important as it can change the treatment plan.
There are many parkinsonian disorders that present similarly, but are not Idiopathic Parkinson's disease. These include Progressive Supranuclear Palsy, Multiple System Atrophy and Corticobasal degeneration. This article outlines the definition, epidemiology, pathophysiology, diagnosis management and prognosis of these conditions.
Conjugated hyperbilirubinemia is a very common condition that affects the infants and young children, which is usually caused by either impairment of biliary excretion of conjugated bilirubin in acquired conditions (such as viral hepatitis) or inherited syndromes of intra-hepatic cholestasis resulting from mutations in specific genes, such as in Dubin-Johnson syndrome.
Monoallelic gene expression refers to the allele-specific expression of genes. Only one allele of the gene is actively transcribed. It can occur in different ways, such as genomic imprinting, random choice of one allele, and X-inactivation. Other allele expressions are balanced and unbalanced expressions. Balanced expressions have both alleles equally expressed, whereas unbalanced ones do not express each allele equally.
Goldilocks principle states that everything should fit in a certain margin; neither too much nor too less. When the amount of gene product changes, it no longer follows the “just right” principle of Goldilocks.
Sex chromosomes have a pivotal role in sex determination. Aberrations of sex chromosomes in diverse ways at different stages of development of an individual result in disorders of sex development (DSD); the understanding of which is often garbled. With a brief introduction to sex determination and sex chromosomes, this article aims to simplify the concept of DSDs.
Physics is an important subject that helps us understand the processes that take place in life. Physics helps the medical personnel in three major ways. First, it helps clarify the functionality of the medical sciences and technology. Second, physics helps explain the physical systems occurring in the body and, finally, understanding physics helps in many other fields providing the framework to solve unsolved problems.
Biliary atresia is an acquired obliteration of the biliary tree leading to neonatal cholestasis, secondary biliary cirrhosis, and portal hypertension. It is the most common indication for liver transplant in children. This article discusses in depth the clinical presentation, classification, etiopathogenesis, workup and management of biliary atresia.
Approximately, 3% of all congenital anomalies are caused by perinatal infections which include toxoplasmosis, other (syphilis, varicella-zoster, parvovirus B19), rubella, cytomegalovirus (CMV), and herpes infections (TORCH). The mother may be asymptomatic during the antenatal period. Diagnosis of the infection in the mother and monitoring the fetus/baby is essential.
Acute pancreatitis is an inflammatory process of the pancreatic tissue with cellular destruction and elevation of serum pancreatic enzymes. The mortality of acute pancreatitis is high specially with necrotizing and infective pancreatitis due to multisystem organ failure. It is the most common cause of gastrointestinal hospitalization in the United States.
Alagille syndrome is a genetic disease characterized by abnormalities in the liver, heart, eye, kidneys, and skeleton with a typical facial appearance. It is an autosomal disorder caused by mutations in the JAG1 gene and NOTCH2 gene. Both sexes irrespective of geographic, racial or ethnic variations are equally affected by this disorder. Jaundice and heart murmurs with characteristic facial appearance are the main symptoms. Blood and urine analysis, ultrasonography, ECG, liver biopsy and genetic tests are the diagnostic measures. Both Therapeutic and surgical interventions are intended based on the patients’ conditions.
This course is all about the first stage of labor. It begins with the onset of contractions. This stage of labor can come on gradually or all of a sudden. Labor can begin with intact amniotic fluid membranes or can start shortly after the membranes have ruptured. Topics that will be discussed include normal and abnormal labor, fetal heart tracings, and obstetrical anesthesia, which involve several treatment modalities that help relieve pain during this stage of labor.
Stage 2 of labor is the part of the normal labor process that begins with full dilation of the maternal cervix and ends with the delivery of the infant. The second stage of labor has a variable length of time. In multiparous women, it can be as short as a couple of minutes. In primiparous women, this stage of labor can last from twenty minutes to two hours. The contractions will last longer, up to 90 seconds per contraction and will be about three to five minutes apart.
Pediatric respiratory disease related to congenital and genetic etiologies are important topics found on the USMLE. Congenital disease to be aware of include Diaphragmatic hernias, congenital cystic adenomatoid malformation, surfactant deficiency, pediatric pulmonary hypoplasia, and bronchopulmonary dysplasia. Genetic disease to be aware of include cystic fibrosis, alpha 1 antitrypsin, and primary ciliary dyskinesia.
Mental abilities change throughout our lives. As the brain matures and then ages, the neural connections undergo rapid expansion followed by progressive degeneration. It is important for physicians to understand the difference between a normal cognitive decline associated with aging and a pathological decline. While normal aging-related cognitive decline does not impair most activities of daily living (ADL), some activities like driving may be compromised. The pathological cognitive decline, on the other hand, is associated with significantly greater morbidity.
Prenatal care, infant care, child and adolescent care aim to prevent diseases and detect other possible illness. Prenatal care is important for women of childbearing age who are either pregnant or plan to be. It not only includes profile assessment to check for the future risks related to pregnancy but also takes into account the education, immunization, and chemoprophylaxis. Infant care is related to screening neonatal jaundice, vaccinations, and other concerns related to sleep, and use of a pacifier. Important screening during early childhood includes birth history, development, home environment, school readiness, diet, physical activity, and sleep.
Due to medical advances over the last half century, people expect to be cured of all their illnesses and live forever. However, death and dying are inevitable. For people facing death as well as for those around them, the process of dying can be stressful. We as physicians can ease the process for our patients, caregivers and ourselves. To be able to do this, we have to understand what dying entails, and then prepare for the event.
Breast masses are uncommon in adolescents but can cause significant distress to the affected individual. They are usually benign fibroadenomas, intraductal papilloma, or phyllodes tumors. Malignant phyllodes tumors and primary breast cancer are very rare in adolescents but have been diagnosed before. Treatment of benign lesions is usually local excision, whereas malignant lesions usually need complete surgical resection. Chemotherapy and radiotherapy are not recommended in adolescents with breast cancer.