AIDS-defining Conditions

Overview

The tables below summarize the defining conditions of acquired immunodeficiency Immunodeficiency Chédiak-Higashi Syndrome syndrome ( AIDS AIDS 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. HIV Infection and AIDS).

Wasting Syndrome

Definition

• An unintentional weight loss Weight loss Decrease in existing body weight. Bariatric Surgery of ≥ 10% in the presence of  ≥ 1 of the following:
  • Chronic diarrhea Diarrhea 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. Diarrhea for ≥ 30 days
  • Chronic weakness
  • Documented fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever for ≥ 30 days 
• Not attributable to a concurrent condition other than HIV HIV Anti-HIV Drugs infection

Possible etiologies and pathophysiology

• Inadequate caloric intake Inadequate Caloric Intake Failure to Thrive
• GI malabsorption Malabsorption General term for a group of malnutrition syndromes caused by failure of normal intestinal absorption of nutrients. Malabsorption and Maldigestion
  • Possibly due to AIDS AIDS 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. HIV Infection and AIDS enteropathy Enteropathy IPEX Syndrome
  • Associated with:
    • Motility Motility The motor activity of the gastrointestinal tract. Gastrointestinal Motility disturbances
    • Mucosal atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
• ↑ Metabolic rate → diversion of energy expenditures to immune function
• Disruption in hormone function
  • ↓ Testosterone Testosterone A potent androgenic steroid and major product secreted by the leydig cells of the testis. Its production is stimulated by luteinizing hormone from the pituitary gland. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to dihydrotestosterone or estradiol. Androgens and Antiandrogens → ↓ muscle mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
  • ↓ Insulin-like growth factor production

Clinical presentation

• Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery characterized by depletion of fat and lean LEAN Quality Measurement and Improvement tissue
• Associated symptoms:
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (intermittent or constant)
  • Diarrhea Diarrhea 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. Diarrhea (≥ 2 stools/day)

Management

• Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
• Treatment of secondary infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease 
• Optimize nutrition:
  • Dietary counseling
  • Multivitamin and mineral supplementation 
• Medical therapy is reserved for those who fail the above measures.
  • Appetite stimulants Stimulants Stimulants are used by the general public to increase alertness and energy, decrease fatigue, and promote mental focus. Stimulants have medical uses for individuals with ADHD and sleep disorders, and are also used in combination with analgesics in pain management. Stimulants
  • Growth hormone
  • Androgenic steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors

AIDS Cholangiopathy

Overview

• Biliary obstruction due to strictures from opportunistic infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease 
• CD4 count < 200 cells/μL (usually < 100 cells/μL)
• Mean survival after diagnosis is 7–12 months.
• Common pathogens:
  • Cryptosporidium Cryptosporidium A genus of coccidian parasites of the family cryptosporidiidae, found in the intestinal epithelium of many vertebrates including humans. Hyper-IgM Syndrome parvum (20%–57% of cases)
  • Cytomegalovirus Cytomegalovirus CMV is a ubiquitous double-stranded DNA virus belonging to the Herpesviridae family. CMV infections can be transmitted in bodily fluids, such as blood, saliva, urine, semen, and breast milk. The initial infection is usually asymptomatic in the immunocompetent host, or it can present with symptoms of mononucleosis. Cytomegalovirus (10%–20% of cases)
  • Herpes simplex Herpes Simplex A group of acute infections caused by herpes simplex virus type 1 or type 2 that is characterized by the development of one or more small fluid-filled vesicles with a raised erythematous base on the skin or mucous membrane. It occurs as a primary infection or recurs due to a reactivation of a latent infection. Congenital TORCH Infections virus Virus 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. Virology
  • Microsporidium
  • Giardia Giardia A genus of flagellate intestinal eukaryotes parasitic in various vertebrates, including humans. Characteristics include the presence of four pairs of flagella arising from a complicated system of axonemes and cysts that are ellipsoidal to ovoidal in shape. Nitroimidazoles
  • Mycobacterium avium Mycobacterium avium A bacterium causing tuberculosis in domestic fowl and other birds. In pigs, it may cause localized and sometimes disseminated disease. The organism occurs occasionally in sheep and cattle. It should be distinguished from the m. avium complex, which infects primarily humans. Mycobacterium complex (MAC)
• Pathophysiology:
  • Opportunistic infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease of the biliary system → chronic biliary inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation → scarring Scarring Inflammation, strictures, and stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)
  • Biliary obstruction → cholestatic liver Liver 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, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy damage

Clinical presentation

• Right upper and epigastric abdominal pain Abdominal Pain Acute Abdomen
• Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
• Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
• Jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice
• Diarrhea Diarrhea 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. Diarrhea (due to Cryptosporidium Cryptosporidium A genus of coccidian parasites of the family cryptosporidiidae, found in the intestinal epithelium of many vertebrates including humans. Hyper-IgM Syndrome)

Diagnosis

• Liver function tests Liver function tests Liver function tests, also known as hepatic function panels, are one of the most commonly performed screening blood tests. Such tests are also used to detect, evaluate, and monitor acute and chronic liver diseases. Liver Function Tests
  • Alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma ↑
  • Aspartate Aspartate One of the non-essential amino acids commonly occurring in the l-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter. Synthesis of Nonessential Amino Acids transaminase Transaminase A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. Catabolism of Amino Acids ( AST AST Enzymes of the transferase class that catalyze the conversion of l-aspartate and 2-ketoglutarate to oxaloacetate and l-glutamate. Liver Function Tests) and alanine Alanine A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases immunity, and provides energy for muscle tissue, brain, and the central nervous system. Synthesis of Nonessential Amino Acids aminotransferase ( ALT ALT An enzyme that catalyzes the conversion of l-alanine and 2-oxoglutarate to pyruvate and l-glutamate. Liver Function Tests) mild to moderately ↑
  • Bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism is usually normal or mildly ↑
• Abdominal ultrasound
  • Dilated intra- and extrahepatic bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy ducts
  • May appear normal
• Magnetic resonance cholangiopancreatography Magnetic resonance cholangiopancreatography Non-invasive diagnostic technique for visualizing the pancreatic ducts and bile ducts without the use of injected contrast media or x-ray. Mri scans provide excellent sensitivity for duct dilatation, biliary stricture, and intraductal abnormalities. Primary Sclerosing Cholangitis ( MRCP MRCP Non-invasive diagnostic technique for visualizing the pancreatic ducts and bile ducts without the use of injected contrast media or x-ray. Mri scans provide excellent sensitivity for duct dilatation, biliary stricture, and intraductal abnormalities. Primary Sclerosing Cholangitis): Assess for biliary strictures and stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS).
• Endoscopic retrograde cholangiopancreatography Endoscopic Retrograde Cholangiopancreatography Fiberoptic endoscopy designed for duodenal observation and cannulation of Vater’s ampulla, in order to visualize the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (Vater) papillotomy may be performed during this procedure. Primary Sclerosing Cholangitis ( ERCP ERCP Fiberoptic endoscopy designed for duodenal observation and cannulation of vater’s ampulla, in order to visualize the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (vater) papillotomy may be performed during this procedure. Primary Sclerosing Cholangitis)
  • Biopsies and biliary aspiration
    • Determine etiology.
    • Exclude cholangiocarcinoma Cholangiocarcinoma A malignant tumor arising from the epithelium of the bile ducts. Rare Malignant Liver Tumors.
  • Allows for intervention on strictures or stenotic lesions

Management

• ERCP ERCP Fiberoptic endoscopy designed for duodenal observation and cannulation of vater’s ampulla, in order to visualize the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (vater) papillotomy may be performed during this procedure. Primary Sclerosing Cholangitis
  • Sphincterotomy Sphincterotomy Surgical incision of a sphincter. Anal Fissure
  • Stenting
• Ursodeoxycholic acid Ursodeoxycholic acid An epimer of chenodeoxycholic acid. It is a mammalian bile acid found first in the bear and is apparently either a precursor or a product of chenodeoxycholate. Its administration changes the composition of bile and may dissolve gallstones. It is used as a cholagogue and choleretic. Primary Biliary Cholangitis
  • For intrahepatic ductal disease
  • Limited data
• Treat underlying infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease (e.g., CMV, Cryptosporidium Cryptosporidium A genus of coccidian parasites of the family cryptosporidiidae, found in the intestinal epithelium of many vertebrates including humans. Hyper-IgM Syndrome)
• Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs

Chronic complications

• Acute cholangitis Acute Cholangitis Acute cholangitis is a life-threatening condition characterized by fever, jaundice, and abdominal pain which develops as a result of stasis and infection of the biliary tract. Septic shock, liver abscess, and multi-organ dysfunction are potential serious complications. Acute Cholangitis
• Liver failure Liver failure Severe inability of the liver to perform its normal metabolic functions, as evidenced by severe jaundice and abnormal serum levels of ammonia; bilirubin; alkaline phosphatase; aspartate aminotransferase; lactate dehydrogenases; and albumin/globulin ratio. Autoimmune Hepatitis
• Cholangiocarcinoma Cholangiocarcinoma A malignant tumor arising from the epithelium of the bile ducts. Rare Malignant Liver Tumors

Ocular Conditions

HIV HIV Anti-HIV Drugs retinopathy Retinopathy Degenerative changes to the retina due to hypertension. Alport Syndrome

• A disease of small blood vessels (microvasculopathy) of the eye
• 70% in advanced HIV HIV Anti-HIV Drugs
• Possible pathophysiology:
  • Interruption of blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure due to:
    • Immune complex deposition
    • ↑ Plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products viscosity
    • HIV HIV Anti-HIV Drugs invasion of vascular endothelium Endothelium A layer of epithelium that lines the heart, blood vessels (vascular endothelium), lymph vessels (lymphatic endothelium), and the serous cavities of the body. Arteries: Histology
  • Deposition of debris
• Clinical presentation: Most are asymptomatic.
• Fundoscopic findings:
  • “Cotton-wool” spots
  • Intraretinal hemorrhages
  • Microaneurysms
  • Telangiectasias Telangiectasias Ataxia-telangiectasia
• No treatment is required.

Herpes simplex Herpes Simplex A group of acute infections caused by herpes simplex virus type 1 or type 2 that is characterized by the development of one or more small fluid-filled vesicles with a raised erythematous base on the skin or mucous membrane. It occurs as a primary infection or recurs due to a reactivation of a latent infection. Congenital TORCH Infections keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2

• Corneal inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation caused by herpes simplex Herpes Simplex A group of acute infections caused by herpes simplex virus type 1 or type 2 that is characterized by the development of one or more small fluid-filled vesicles with a raised erythematous base on the skin or mucous membrane. It occurs as a primary infection or recurs due to a reactivation of a latent infection. Congenital TORCH Infections virus Virus 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. Virology ( HSV HSV Herpes simplex virus (HSV) is a double-stranded DNA virus belonging to the family Herpesviridae. Herpes simplex virus commonly causes recurrent infections involving the skin and mucosal surfaces, including the mouth, lips, eyes, and genitals. Herpes Simplex Virus 1 and 2) infection
• Types:
  • Epithelial (dendritic) keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
  • Disciform (localized endotheliitis) keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
  • Stromal keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
• Clinical presentation:
  • Tearing
  • Foreign body Foreign Body Foreign Body Aspiration sensation
  • Vision Vision Ophthalmic Exam loss
    • Reversible in disciform keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
    • Irreversible in stromal keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
  • Photophobia Photophobia Abnormal sensitivity to light. This may occur as a manifestation of eye diseases; migraine; subarachnoid hemorrhage; meningitis; and other disorders. Photophobia may also occur in association with depression and other mental disorders. Migraine Headache
• Slit-lamp examination Slit-Lamp Examination Blepharitis:
  • Dendritic corneal lesions are diagnostic.
• Management:
  • Topical therapy:
    • Acyclovir Acyclovir A guanosine analog that acts as an antimetabolite. Viruses are especially susceptible. Used especially against herpes. Herpes Zoster (Shingles), ganciclovir Ganciclovir An acyclovir analog that is a potent inhibitor of the herpesvirus family including cytomegalovirus. Ganciclovir is used to treat complications from aids-associated cytomegalovirus infections. Antivirals for Herpes Virus, or trifluridine
    • Corticosteroids Corticosteroids Chorioretinitis for stromal keratitis Keratitis Inflammation of the cornea. Herpes Simplex Virus 1 and 2
  • Systemic therapy: acyclovir Acyclovir A guanosine analog that acts as an antimetabolite. Viruses are especially susceptible. Used especially against herpes. Herpes Zoster (Shingles) or valacyclovir Valacyclovir A prodrug of acyclovir that is used in the treatment of herpes zoster and herpes simplex virus infection of the skin and mucous membranes, including genital herpes. Herpes Zoster (Shingles)

Retinitis

CMV retinitis CMV retinitis Infection of the retina by cytomegalovirus characterized by retinal necrosis, hemorrhage, vessel sheathing, and retinal edema. Cytomegalovirus retinitis is a major opportunistic infection in AIDS patients and can cause blindness. Retinal Detachment:

• CD4 count < 50 cells/μL
• Pathophysiology:
  • Hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases spread of CMV to the eye
  • Causes retinal necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage and edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema → atrophic scar Scar Dermatologic Examination tissue
  • Tears in scar Scar Dermatologic Examination tissue → retinal detachment Retinal detachment Retinal detachment is the separation of the neurosensory retina from the retinal pigmented epithelium and choroid. Rhegmatogenous retinal detachment, the most common type, stems from a break in the retina, allowing fluid to accumulate in the subretinal space. Retinal Detachment
• Clinical presentation:
  • Painless central vision loss Central Vision Loss Macular Degeneration
  • Scotomata ( blind spots Blind spots A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of eye diseases (e.g., retinal diseases and glaucoma); optic nerve diseases, and other conditions. Chorioretinitis)
  • Floaters Floaters Chorioretinitis
  • Photopsia Photopsia Chorioretinitis (flashing lights)
• Fundoscopic findings:
  • Perivascular yellow-white retinal lesions
  • Associated hemorrhage
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Ganciclovir Ganciclovir An acyclovir analog that is a potent inhibitor of the herpesvirus family including cytomegalovirus. Ganciclovir is used to treat complications from aids-associated cytomegalovirus infections. Antivirals for Herpes Virus, valganciclovir, or foscarnet Foscarnet An antiviral agent used in the treatment of cytomegalovirus retinitis. Foscarnet also shows activity against human herpesviruses and HIV. Antivirals for Herpes Virus

Toxoplasma Toxoplasma Toxoplasmosis is an infectious disease caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. Felines are the definitive host, but transmission to humans can occur through contact with cat feces or the consumption of contaminated foods. The clinical presentation and complications depend on the host’s immune status. Toxoplasma/Toxoplasmosis chorioretinitis Chorioretinitis Chorioretinitis is the inflammation of the posterior segment of the eye, including the choroid and the retina. The condition is usually caused by infections, the most common of which is toxoplasmosis. Some of these infections can affect the fetus in utero and present as congenital abnormalities. Chorioretinitis:

• Ocular disease due to Toxoplasma Toxoplasma Toxoplasmosis is an infectious disease caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. Felines are the definitive host, but transmission to humans can occur through contact with cat feces or the consumption of contaminated foods. The clinical presentation and complications depend on the host’s immune status. Toxoplasma/Toxoplasmosis gondii
• CD4 count < 100 cells/μL
• Pathophysiology:
  • Focal necrotizing retinitis
  • Granulomatous choroid Choroid The thin, highly vascular membrane covering most of the posterior of the eye between the retina and sclera. Eye: Anatomy inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation
• Clinical presentation:
  • Blurred vision Blurred Vision Retinal Detachment
  • Floaters Floaters Chorioretinitis
  • Eye pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Fundoscopic findings:
  • Raised, yellow-white cotton lesions
  • Nonvascular distribution
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Pyrimethamine Pyrimethamine One of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis. Antimalarial Drugs + sulfadiazine Sulfadiazine One of the short-acting sulfonamides used in combination with pyrimethamine to treat toxoplasmosis in patients with acquired immunodeficiency syndrome and in newborns with congenital infections. Sulfonamides and Trimethoprim + folinic acid (leucovorin)

Varicella zoster retinitis:

• Also known as progressive outer retinal necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
• CD4 < 100 cells/μL
• Pathophysiology:
  • Rapidly progressing retinal necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
  • Leads to retinal detachment Retinal detachment Retinal detachment is the separation of the neurosensory retina from the retinal pigmented epithelium and choroid. Rhegmatogenous retinal detachment, the most common type, stems from a break in the retina, allowing fluid to accumulate in the subretinal space. Retinal Detachment
• Clinical presentation:
  • Vision Vision Ophthalmic Exam loss
  • Rapid progression to blindness Blindness The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of eye diseases; optic nerve diseases; optic chiasm diseases; or brain diseases affecting the visual pathways or occipital lobe. Retinopathy of Prematurity
  • Some patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may have eye pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Fundoscopic findings:
  • Patchy, peripheral retinal necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
  • No involvement of retinal vasculature
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Intravenous and intravitreal antiviral Antiviral Antivirals for Hepatitis B medications ( ganciclovir Ganciclovir An acyclovir analog that is a potent inhibitor of the herpesvirus family including cytomegalovirus. Ganciclovir is used to treat complications from aids-associated cytomegalovirus infections. Antivirals for Herpes Virus, foscarnet Foscarnet An antiviral agent used in the treatment of cytomegalovirus retinitis. Foscarnet also shows activity against human herpesviruses and HIV. Antivirals for Herpes Virus, valganciclovir)

Central Nervous System Conditions

HIV-associated dementia Dementia Major neurocognitive disorders (NCD), also known as dementia, are a group of diseases characterized by decline in a person’s memory and executive function. These disorders are progressive and persistent diseases that are the leading cause of disability among elderly people worldwide. Major Neurocognitive Disorders

• Previously known as:
  • AIDS AIDS 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. HIV Infection and AIDS dementia Dementia Major neurocognitive disorders (NCD), also known as dementia, are a group of diseases characterized by decline in a person’s memory and executive function. These disorders are progressive and persistent diseases that are the leading cause of disability among elderly people worldwide. Major Neurocognitive Disorders complex
  • HIV HIV Anti-HIV Drugs encephalopathy Encephalopathy Hyper-IgM Syndrome
  • HIV HIV Anti-HIV Drugs encephalitis Encephalitis 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. Encephalitis
• CD4 count < 200 cells/μL
• Clinical presentation:
  • Cognitive dysfunction
    • Memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment loss
    • Poor attention Attention Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating. Psychiatric Assessment and concentration
    • Impaired executive functioning
  • Behavioral and mood changes
    • Apathy Apathy Lack of emotion or emotional expression; a disorder of motivation that persists over time. Wernicke Encephalopathy and Korsakoff Syndrome
    • Decreased motivation
    • Irritability
    • Sleeplessness
    • Restlessness and anxiety Anxiety Feelings or emotions of dread, apprehension, and impending disaster but not disabling as with anxiety disorders. Generalized Anxiety Disorder
    • Psychosis, paranoia, and hallucinations Hallucinations Subjectively experienced sensations in the absence of an appropriate stimulus, but which are regarded by the individual as real. They may be of organic origin or associated with mental disorders. Schizophrenia
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology symptoms
    • Slowed movement and gait Gait Manner or style of walking. Neurological Examination
    • Saccadic eye movements Saccadic Eye Movements Internuclear Ophthalmoplegia
    • Dysdiadochokinesia Dysdiadochokinesia Difficulty with rapid alternating movements Cerebellar Disorders
    • Hyperreflexia
    • Frontal Frontal The bone that forms the frontal aspect of the skull. Its flat part forms the forehead, articulating inferiorly with the nasal bone and the cheek bone on each side of the face. Skull: Anatomy release signs (grasp, root, glabellar reflexes)
• Diagnosis:
  • Neuropsychological testing aids AIDS 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. HIV Infection and AIDS in the diagnosis.
    • ≥ 2 standard deviations below the mean in ≥ 2 cognitive domains on neuropsychological testing
    • Concomitant impairment in activities of daily living
    • Cannot be explained by other conditions
  • Magnetic resonance imaging (MRI)
    • 1st-choice imaging modality
    • Diffuse, patchy white matter White Matter The region of central nervous system that appears lighter in color than the other type, gray matter. It mainly consists of myelinated nerve fibers and contains few neuronal cell bodies or dendrites. Brown-Séquard Syndrome hyperintensity
    • Rule out other causes of encephalopathy Encephalopathy Hyper-IgM Syndrome.
  • Lumbar puncture Lumbar Puncture Febrile Infant with cerebral spinal fluid (CSF) analysis
    • Lymphocytic pleocytosis Pleocytosis Tick-borne Encephalitis Virus
    • CSF HIV HIV Anti-HIV Drugs viral load Viral load The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a surrogate marker in disease progression. HIV Infection and AIDS is generally > plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products viral load Viral load The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a surrogate marker in disease progression. HIV Infection and AIDS
    • Findings are nonspecific.
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Safety assessment
  • Psychiatric evaluation

Central nervous system Central nervous system The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. Nervous System: Anatomy, Structure, and Classification (CNS) toxoplasmosis Toxoplasmosis Toxoplasmosis is an infectious disease caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. Felines are the definitive host, but transmission to humans can occur through contact with cat feces or the consumption of contaminated foods. The clinical presentation and complications depend on the host’s immune status. Toxoplasma/Toxoplasmosis

• Most common CNS infection in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with AIDS AIDS 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. HIV Infection and AIDS
• CD4 count < 100 cells/μL
• Etiology:
  • Reactivation Reactivation Herpes Simplex Virus 1 and 2 of prior infection with T. gondii
  • Transmitted through ingestion of oocysts after contact with infected cat feces
• Clinical presentation:
  • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • Altered mental status Altered Mental Status Sepsis in Children
    • Dull affect
    • Stupor
    • Coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma
  • Focal neurologic deficits Neurologic Deficits High-Risk Headaches
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
• Diagnosis:
  • Computed tomography (CT) or MRI
    • Single or multiple ring-enhancing lesions
    • MRI is more sensitive.
  • Lumbar puncture Lumbar Puncture Febrile Infant with CSF analysis CSF analysis Meningitis
    • Lymphocytic pleocytosis Pleocytosis Tick-borne Encephalitis Virus 
    • ↑ Protein 
    • Polymerase chain reaction Polymerase chain reaction Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) ( PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR)) to identify T. gondii
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Pyrimethamine Pyrimethamine One of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis. Antimalarial Drugs + sulfadiazine Sulfadiazine One of the short-acting sulfonamides used in combination with pyrimethamine to treat toxoplasmosis in patients with acquired immunodeficiency syndrome and in newborns with congenital infections. Sulfonamides and Trimethoprim + folinic acid (leucovorin)
  • TMP-SMX is an alternative.
  • Prophylaxis Prophylaxis Cephalosporins
    • TMP-SMX
    • Indicated in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a CD4 count < 100 cells/μL

Primary CNS lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum

• Overview:
  • Extra-nodal non-Hodgkin’s lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum
  • Associated with Epstein-Barr virus Epstein-Barr Virus Epstein-Barr virus (EBV) is a linear, double-stranded DNA virus belonging to the Herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus ( EBV EBV Epstein-barr virus (EBV) is a linear, double-stranded DNA virus belonging to the herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus) infection
  • CD4 count < 50 cells/μL
• Clinical presentation:
  • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
  • Confusion and lethargy Lethargy A general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction. Hyponatremia 
  • Focal neurologic deficits Neurologic Deficits High-Risk Headaches ( hemiparesis Hemiparesis The term hemiparesis refers to mild to moderate weakness involving one side of the body. Epidural Hemorrhage)
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
  • Constitutional (“B symptoms”)
    • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
    • Night sweats Night sweats Tuberculosis
    • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
• Diagnosis: 
  • CT and MRI: usually a single ring-enhancing lesion Ring-enhancing lesion Paracoccidioides/Paracoccidioidomycosis
  • Lumbar puncture Lumbar Puncture Febrile Infant and CSF analysis CSF analysis Meningitis
    • PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) for EBV EBV Epstein-barr virus (EBV) is a linear, double-stranded DNA virus belonging to the herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure
    • Cytology
  • Brain biopsy Brain biopsy JC Virus and BK Virus
• Management:
  • Chemotherapy Chemotherapy Osteosarcoma ( methotrexate Methotrexate An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy)
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs

Progressive multifocal Multifocal Retinoblastoma leukoencephalopathy ( PML PML An opportunistic viral infection of the central nervous system associated with conditions that impair cell-mediated immunity (e.g., acquired immunodeficiency syndrome and other immunologic deficiency syndromes; hematologic neoplasms; immunosuppression; and collagen diseases). The causative organism is JC polyomavirus (JC virus) which primarily affects oligodendrocytes, resulting in multiple areas of demyelination. Clinical manifestations include dementia; ataxia; visual disturbances; and other focal neurologic deficits, generally progressing to a vegetative state within 6 months. JC Virus and BK Virus)

• Overview:
  • Demyelinating disease of the CNS 
  • Caused by reactivation Reactivation Herpes Simplex Virus 1 and 2 of John Cunningham polyomavirus (JCV)
    • Acquired during childhood
    • Remains latent in organs ( kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy, lymphoid organs Lymphoid organs A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs, CNS)
  • CD4 count < 200 cells/μL
• Clinical presentation:
  • Rapidly progressive symptoms 
  • Hemiparesis Hemiparesis The term hemiparesis refers to mild to moderate weakness involving one side of the body. Epidural Hemorrhage (most common)
  • Aphasia Aphasia A cognitive disorder marked by an impaired ability to comprehend or express language in its written or spoken form. This condition is caused by diseases which affect the language areas of the dominant hemisphere. Clinical features are used to classify the various subtypes of this condition. General categories include receptive, expressive, and mixed forms of aphasia. Ischemic Stroke and dysarthria Dysarthria Disorders of speech articulation caused by imperfect coordination of pharynx, larynx, tongue, or face muscles. This may result from cranial nerve diseases; neuromuscular diseases; cerebellar diseases; basal ganglia diseases; brain stem diseases; or diseases of the corticobulbar tracts. The cortical language centers are intact in this condition. Wilson Disease
  • Hemianopia Hemianopia Transient Ischemic Attack (TIA)
  • Gait ataxia Gait ataxia Impairment of the ability to coordinate the movements required for normal ambulation (walking) which may result from impairments of motor function or sensory feedback. This condition may be associated with brain diseases (including cerebellar diseases and basal ganglia diseases); spinal cord diseases; or peripheral nervous system diseases. Friedreich Ataxia
  • Cognitive impairment
  • Impaired vigilance
  • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures (rare)
• Diagnosis:
  • CT or MRI
    • Disseminated, non-enhancing white matter White Matter The region of central nervous system that appears lighter in color than the other type, gray matter. It mainly consists of myelinated nerve fibers and contains few neuronal cell bodies or dendrites. Brown-Séquard Syndrome lesions 
    • No mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast effect
  • Lumbar puncture Lumbar Puncture Febrile Infant with CSF analysis CSF analysis Meningitis: PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) for JCV DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure
  • Brain biopsy Brain biopsy JC Virus and BK Virus
• Management:
  • Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Supportive care

Bacillary Angiomatosis

Overview

• CD4 count < 100 cells/μL
• Etiology:
  • Causative organisms:
    • Bartonella henselae Bartonella henselae A species of gram-negative bacteria that is the etiologic agent of bacillary angiomatosis. This organism can also be a cause of cat-scratch disease in immunocompetent patients. Bartonella (most common)
    • B. quintana
  • Transmission:
    • Fleas and lice
    • Cat scratches
• Pathophysiology:
  • Bartonella Bartonella Bartonella is a genus of gram-negative bacteria in the family Bartonellaceae. As a facultative intracellular parasite, Bartonella can infect healthy people as well as act as an opportunistic pathogen. Bartonella species are transmitted by vectors such as ticks, fleas, sandflies, and mosquitoes. B. henselae is the most common of the 3 species known to cause human disease. Bartonella infection → vascular proliferation → angiomatous skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions lesions
  • Involvement of other organs:
    • Respiratory tract
    • Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
    • Lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
    • GI tract
    • Brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification

Clinical presentation

• Cutaneous lesions 
  • Protuberant, red papules or nodules 
  • Friable (tend to bleed profusely with trauma)
• Subcutaneous nodules that may ulcerate
• Painful, osteolytic bone lesions Bone Lesions Multiple Myeloma
  • Frequently of the long bones Long bones Length greater than width. Bones: Structure and Types
  • Associated with an overlying cellulitic plaque Plaque Primary Skin Lesions
• Smooth, purple, mucosal papules or plaques

Diagnosis

• Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma of affected tissue
  • Vascular proliferation
  • Protuberant, plump endothelial cells
  • Scattered neutrophils Neutrophils Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes. Innate Immunity: Phagocytes and Antigen Presentation and lymphocytes Lymphocytes Lymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone marrow, starting from hematopoietic stem cells (HSCs) and progressing to common lymphoid progenitors (CLPs). B and T lymphocytes and natural killer (NK) cells arise from the lineage. Lymphocytes: Histology
  • Dark-staining bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology seen with Warthin-Starry silver staining
• Blood or tissue cultures
• PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR)

Management

• Antibiotic therapy
  • Erythromycin Erythromycin A bacteriostatic antibiotic macrolide produced by streptomyces erythreus. Erythromycin a is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50s ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. Macrolides and Ketolides
  • Doxycycline
• Monitor antibody titers
• Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs

Kaposi’s Sarcoma

Overview

• Aggressive, malignant vascular tumors
• CD4 count < 500 cells/μL
• Etiology:
  • Human herpesvirus type 8 (HHV-8)
  • Commonly transmitted via saliva Saliva The clear, viscous fluid secreted by the salivary glands and mucous glands of the mouth. It contains mucins, water, organic salts, and ptyalin. Salivary Glands: Anatomy and sexual contact

Clinical presentation

• Cutaneous lesions
  • Common sites:
    • Lower extremities
    • Face
    • Oral mucosa Oral mucosa Lining of the oral cavity, including mucosa on the gums; the palate; the lip; the cheek; floor of the mouth; and other structures. The mucosa is generally a nonkeratinized stratified squamous epithelium covering muscle, bone, or glands but can show varying degree of keratinization at specific locations. Stomatitis
    • Genitalia
  • Appearance:
    • Elliptical
    • Assorted colors (pink, red, purple, brown)
    • Papular or plaque-like 
    • Not painful or pruritic
    • Yellow-green peri-lesional “halo”
    • Associated lymphedema Lymphedema Edema due to obstruction of lymph vessels or disorders of the lymph nodes. Lymphatic Filariasis (Elephantiasis)
• Intraoral lesions
  • Common sites:
    • Hard palate Hard palate The anteriorly located rigid section of the palate. Palate: Anatomy
    • Gingiva
  • Trauma can lead to bleeding, ulceration Ulceration Corneal Abrasions, Erosion, and Ulcers, or secondary infection.
• GI tract lesions
  • Hemorrhagic or submucosal nodules
  • Can occur anywhere along the GI tract
  • Symptoms:
    • Asymptomatic (most common)
    • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery and malabsorption Malabsorption General term for a group of malnutrition syndromes caused by failure of normal intestinal absorption of nutrients. Malabsorption and Maldigestion
    • Abdominal pain Abdominal Pain Acute Abdomen
    • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia 
    • Intestinal obstruction Intestinal obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis
    • GI bleeding
• Pulmonary manifestations
  • Cherry-red, elevated lesions
  • Nodular, interstitial, or alveolar infiltrates
  • Pleural effusion Pleural Effusion 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. Pleural Effusion
  • Symptoms:
    • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
    • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
    • Cough and hemoptysis Hemoptysis 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. Hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. Hemoptysis
    • Chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways

Diagnosis

Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma confirms the diagnosis.

• Samples may be obtained from:
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions lesions
  • Endoscopy Endoscopy Procedures of applying endoscopes for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. Transluminal, to examine or perform surgery on the interior parts of the body. Gastroesophageal Reflux Disease (GERD) (GI symptoms)
  • Bronchoscopy Bronchoscopy Endoscopic examination, therapy or surgery of the bronchi. Laryngomalacia and Tracheomalacia ( pulmonary involvement Pulmonary involvement Coccidioides/Coccidioidomycosis)
• Findings:
  • Angiogenesis Angiogenesis Bartonella with aberrant proliferation of small vessels
    • Vessels lack a basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN).
    • Microhemorrhages
    • Hemosiderin Hemosiderin Heme Metabolism deposition
  • Whorls of spindle-shaped cells
  • Leukocyte infiltration

Management

• Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs can lead to a marked response.
• Local therapies to induce regression Regression Corneal Abrasions, Erosion, and Ulcers of tumors
  • Intralesional chemotherapy Chemotherapy Osteosarcoma ( vinblastine Vinblastine Antitumor alkaloid isolated from vinca rosea. Microtubule and Topoisomerase Inhibitors)
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy
  • Topical alitretinoin
• Systemic chemotherapy Chemotherapy Osteosarcoma for advanced or rapidly progressing disease

Mycobacterium avium Complex Infection

Overview

• CD4 count < 50 cells/μL
• Causative organisms:
  • M. avium
  • M. intracellulare
• Transmission:
  • Inhalation
  • Ingestion of contaminated food or water
• Bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology disseminate through the lymphatic system Lymphatic system A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs.

Clinical presentation

• Disseminated disease
  • High fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
  • Night sweats Night sweats Tuberculosis
  • Abdominal pain Abdominal Pain Acute Abdomen
  • Diarrhea Diarrhea 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. Diarrhea
• Focal lymphadenitis Lymphadenitis Inflammation of the lymph nodes. Peritonsillar Abscess
  • Commonly results from immune reconstitution inflammatory syndrome
    • Occurs after initiation of antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
    • Paradoxical worsening of preexisting infectious conditions
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • Lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy
• Other localized manifestations
  • Mastitis Mastitis 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). Mastitis
  • Subcutaneous nodules
  • Osteomyelitis Osteomyelitis 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. Osteomyelitis
  • Granulomatous hepatitis
  • Paravertebral abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease
  • Brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease
  • Lung infiltrates
  • Intestinal involvement

Diagnosis

• Blood cultures
• Tissue aspirate ( lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs node)
• Associated laboratory abnormalities:
  • Anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types
  • Thrombocytopenia Thrombocytopenia 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. Thrombocytopenia 
  • ↑ Alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma
  • ↑ Lactate dehydrogenase Lactate Dehydrogenase Osteosarcoma

Management

• Macrolide plus ethambutol Ethambutol An antitubercular agent that inhibits the transfer of mycolic acids into the cell wall of the tubercle Bacillus. It may also inhibit the synthesis of spermidine in mycobacteria. The action is usually bactericidal, and the drug can penetrate human cell membranes to exert its lethal effect. Antimycobacterial Drugs 
• Rifabutin Rifabutin A broad-spectrum antibiotic that is being used as prophylaxis against disseminated Mycobacterium avium complex infection in HIV-positive patients. Diseases of the Uvea may be added for:
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship failing antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a high bacterial burden
• Antiretroviral therapy Antiretroviral therapy Antiretroviral therapy (ART) targets the replication cycle of the human immunodeficiency virus (HIV) and is classified based on the viral enzyme or mechanism that is inhibited. The goal of therapy is to suppress viral replication to reach the outcome of undetected viral load. Anti-HIV Drugs