Toxoplasma/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. Patients who are immunocompetent usually have no symptoms, whereas those who are immunocompromised may develop CNS toxoplasmosis or 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. The diagnosis is often made based on serology or PCR. Patients who are immunocompetent may not need any treatment. Patients who are immunocompromised or those with severe disease may require combination therapy with pyrimethamine, sulfadiazine, and leucovorin.

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Table of Contents

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General Characteristics and Epidemiology

General features of Toxoplasma

General characteristics:

  • Obligate intracellular parasite
  • Protozoan parasite

Morphologic forms:

  • Oocyst: 
    • Shed in feline feces
    • Takes 1–5 days to sporulate in the environment and become infective
  • Tachyzoite (also called trophozoite):
    • Obligate intracellular form 
    • Crescent-shaped form with a central nucleus
    • Responsible for cell invasion and clinical disease
    • Multiplies rapidly
  • Bradyzoite: 
    • Quiescent
    • Forms a thick wall around itself (tissue cyst)
    • Resistant to digestive enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body's constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes
    • Killed by freezing and normal cooking temperatures

Clinically relevant species

Toxoplasmosis is caused by Toxoplasma gondii.

Epidemiology

  • Found worldwide, but more common in tropical regions
  • 225,000 cases reported each year in the United States
  • Approximately 50% of individuals have antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins against T. gondii:
    • Approximately 11% of the population > 6 years of age in the United States
    • Up to 78% of the population in some areas of Brazil

Pathogenesis

Hosts

  • Felines are the only definitive host.
  • Infections can occur in a wide range of vertebrate intermediate hosts (including humans).

Transmission

  • Oral route: 
    • Ingestion of oocysts passed in the feces of infected felines 
    • Ingestion of infected meat that is raw or undercooked (tissue cyst form)
  • Blood transfusion or organ transplantation Organ Transplantation Transplantation is a procedure that involves the removal of an organ or living tissue and placing it into a different part of the body or into a different person. Organ transplantations have become the therapeutic option of choice for many individuals with end-stage organ failure. Organ Transplantation 
  • Vertical transmission

Life cycle and pathophysiology

Life cycle:

  • Oocysts are shed in the cat’s feces → ingested by an intermediate host (e.g., mammals, birds)
  • Oocysts transform into tachyzoites → localize in neural and muscle tissues → develop into tissue cysts
  • Cat consumes an infected intermediate host’s tissue → organism undergoes sexual cycle → cycle continues 

Life cycle and pathophysiology in humans:

  • Transmission to a human host → bradyzoites released from cysts (or sporozoites from oocysts)
  • Transformation to tachyzoites → multiply rapidly in GI cells → rupture cells
  • Transported in the lymphatics and disseminate in the bloodstream to: 
    • Skeletal muscle
    • Myocardium
    • Brain
    • Eyes
  • Immune system generally controls the replication of tachyzoites.
  • Bradyzoites develop cysts and remain dormant → can remain dormant for years
Life cycle of toxoplasma gondii

Life cycle of Toxosplasma gondii

Image: “3421” by CDC/Alexander J. da Silva, PhD; Melanie Moser. License: Public Domain

Clinical Presentation

The clinical presentation of toxoplasmosis can vary depending on the host’s immune function and organs involved. The following table summarizes the various diseases:

Table: Clinical presentations of toxoplasmosis
Host Disease Presentation
Immunocompetent host Subclinical infection (approximately 90% of cases) Asymptomatic
Acute systemic disease Common signs and 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
  • Sore throat
  • Bilateral nontender cervical 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
  • Malaise
  • Nonpruritic maculopapular rash
  • Hepatosplenomegaly
  • Headache
Uncommon manifestations:
  • Pneumonitis
  • Myocarditis Myocarditis 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. Myocarditis
  • Hepatitis
  • Posterior uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea
  • Polymyositis Polymyositis Polymyositis (PM) is an autoimmune inflammatory myopathy caused by T cell-mediated muscle injury. The etiology of PM is unclear, but there are several genetic and environmental associations. Polymyositis is most common in middle-aged women and rarely affects children. Polymyositis
  • 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
Immunocompromised host (e.g., AIDS) CNS toxoplasmosis (AIDS-defining illness, CD4 count < 100 cells/µL)
  • 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
  • Headache
  • Focal neurologic deficits
  • Mental status changes
  • Seizures
Chorioretinitis Symptoms:
  • Floaters
  • Blurred or loss of vision
  • Eye pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain
Fundoscopic findings:
  • Raised yellow-white cotton lesions
  • Nonvascular distribution
Pneumonitis
  • 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
  • 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
  • Nonproductive cough
Fetus, newborn Newborn 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, or infant Congenital toxoplasmosis Classic triad:
  • Chorioretinitis
  • Hydrocephalus
  • Diffuse intracranial calcifications
Signs and 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
  • Hepatosplenomegaly
  • Lymphadenopathy
  • 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
  • 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 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
  • Delayed growth
  • Petechiae and purpura (“blueberry muffin” rash)
  • Macrocephaly
  • Pneumonitis
  • Seizures
  • Sensorineural hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss
CD4: cluster of differentiation 4
Toxoplasma retinochoroiditis

Fundoscopy of Toxoplasma 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:
Note the yellow-white cotton lesions in both the right eye (A) and left eye (B).

Image: “Retinochoroiditis” by Department of Ophthalmology and Visual Sciences, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY 10467, USA. License: CC BY 2.0

Diagnosis

The diagnostic workup will be guided by the patient’s clinical presentation.

Laboratory evaluation

  • Serologic testing (ELISA):
    • IgM antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins
      • Appear within 1 week of symptom onset
      • A positive test indicates active infection.
    • IgG antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins:
      • Appear within 2 weeks of symptom onset
      • Persist for life
  • PCR:
    • Detects parasite DNA DNA The molecule DNA is the repository of heritable genetic information. In humans, DNA is contained in 23 chromosome pairs within the nucleus. The molecule provides the basic template for replication of genetic information, RNA transcription, and protein biosynthesis to promote cellular function and survival. DNA Types and Structure
    • Samples can be obtained from:
      • Blood
      • CSF
      • Aqueous humor
      • Bronchoalveolar lavage
  • Supporting laboratory studies:
    • Negative heterophile antibody test → rules out mononucleosis Mononucleosis 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. Mononucleosis
    • Lymphocytosis Lymphocytosis WBCs develop from stem cells in the bone marrow and are called leukocytes when circulating in the bloodstream. Lymphocytes are 1 of the 5 subclasses of WBCs. Lymphocytosis is an increase in the number or proportion of the lymphocyte subclass of WBCs, often as a result of an immune response to infection (known as reactive lymphocytosis). Lymphocytosis (with or without atypical cells)
    • Mild transaminitis

Histopathology

  • Provides a definitive diagnosis, but rarely required
  • Lymph node findings:
    • Reactive follicular hyperplasia
    • Irregular clusters of tissue macrophages with eosinophilic cytoplasm
  • Brain findings:
    • Patchy, diffuse encephalitis
    • Cyst lesions
    • Necrotic regions
    • Granulomas
    • Lymphocytic vasculitis
  • Ocular findings:
    • Segmental panophthalmitis
    • Necrosis
    • Tissue cysts and tachyzoites
Neurotoxoplasmosis histology

Photomicrograph of a Toxoplasma gondii tissue cyst in a brain tissue specimen

Image: “16543” by CDC/Dr. Martin Hicklin. License: Public Domain

Imaging

Brain imaging may be performed if CNS or congenital toxoplasmosis is suspected.

  • Options:
    • CT
    • MRI
  • Findings in CNS toxoplasmosis:
    • Single or multiple ring-enhancing lesions
    • Inflammatory changes
  • Findings in congenital toxoplasmosis:
    • Scattered calcifications 
    • Hydrocephalus 
    • Cortical atrophy

Management and Prevention

Management

Patients who are immunocompetent typically do not require treatment. However, treatment is needed for patients who are immunocompromised, pregnant, or with severe or prolonged symptoms.

  • Combination medical therapy:
    • Pyrimethamine (inhibits dihydrofolate reductase)
    • Sulfadiazine (inhibits dihydropteroate synthetase)
    • Leucovorin (folinic acid, prevents folic acid deficiency)
  • Corticosteroids may be added in CNS toxoplasmosis to reduce cerebral 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 if mass effect is present.
  • Ensure that patients with AIDS are started on 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.

Prevention and prophylaxis

  • General advice:
    • Wash hands after handling raw meat or cat litter.
    • Thoroughly cook meat.
  • Pregnant patients:
    • Routine antibody screening in pregnant women is not recommended.
    • Avoid cats.
    • Do not clean litter boxes (if unavoidable, wear gloves).
  • Patients with AIDS: long-term sulfamethoxazole- trimethoprim Trimethoprim The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim when CD4 < 100 cells/µL

Differential Diagnosis

  • Infectious mononucleosis Mononucleosis 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. Mononucleosis: a disease caused by EBV that is characterized by fever, fatigue, 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, and pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis. Atypical lymphocytosis may be seen. The diagnosis is based on clinical features and tests, such as a positive heterophile antibody test or serology. Management is supportive. 
  • CMV mononucleosis Mononucleosis 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. Mononucleosis: a disease caused by CMV. Patients may present with fevers, 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, hepatitis, and atypical lymphocytosis. However, pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis is absent. Positive CMV serologic testing provides the diagnosis. The disease is self-limiting.
  • Acute human immunodeficiency 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: Overview (HIV) infection: a sexually transmitted or blood-borne disease caused by HIV. The presentation of HIV is marked by constitutional symptoms such as 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 and fever. Further progression may lead to opportunistic infections and malignancies. Diagnosis is by enzyme immunoassay. Additional tests include HIV viral load determination, genotyping, and CD4+ T lymphocyte count. Immediate treatment with combination 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 is recommended.
  • Tularemia: a rare infection caused by Francisella tularensis acquired by contact with animal tissue, ticks, or biting flies. The infection manifests as a papule, followed by fever, headache, and suppurative 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. Tularemia may have multiorgan involvement. Diagnosis is based on culture of blood and infected tissues. Treatment is with antibiotics.
  • Cat-scratch disease: an infection caused by 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 henselae, a gram-negative bacillus Bacillus Bacillus are aerobic, spore-forming, gram-positive bacilli. Two pathogenic species are Bacillus anthracis (B. anthracis) and B. cereus. Bacillus. Patients usually present with fever, weight loss, and tender 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 after being bitten or scratched by a cat. The diagnosis is confirmed with serology or PCR. Symptomatic treatment is recommended and azithromycin is given for severe illness.
  • Extrapulmonary tuberculosis Tuberculosis 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. Tuberculosis: a disseminated mycobacterial infection. The presentation of extrapulmonary tuberculosis Tuberculosis 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. Tuberculosis includes meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis, pericarditis Pericarditis 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. Pericarditis, lymphadenitis, and 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 infection, and can vary depending on the site involved. The diagnosis is based on the detection of acid-fast bacilli by culturing body fluids or tissue samples. Treatment involves combination therapy with isoniazid, rifampin, pyrazinamide, and ethambutol.
  • Hodgkin disease: a malignancy of B lymphocytes B lymphocytes B lymphocytes, also known as B cells, are important components of the adaptive immune system. In the bone marrow, the hematopoietic stem cells go through a series of steps to become mature naive B cells. The cells migrate to secondary lymphoid organs for activation and further maturation. B Cells within the lymph nodes. Patients present with 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, night sweats, weight loss, fever, splenomegaly Splenomegaly Splenomegaly is pathologic enlargement of the spleen that is attributable to numerous causes, including infections, hemoglobinopathies, infiltrative processes, and outflow obstruction of the portal vein. Splenomegaly, and hepatomegaly. Diagnostic tests Diagnostic tests Diagnostic tests are important aspects in making a diagnosis. Some of the most important epidemiological values of diagnostic tests include sensitivity and specificity, false positives and false negatives, positive and negative predictive values, likelihood ratios, and pre-test and post-test probabilities. Epidemiological Values of Diagnostic Tests include lymph node histological analysis, blood tests, CT, and PET. Management includes chemotherapy and radiotherapy.
  • Neurocysticercosis: an infection caused by ingestion of Taenia Taenia Taenia belong to the Cestoda class of helminths. Humans are infected with these tapeworms by eating undercooked beef (T. saginata) or pork (T. solium and T. asiatica). Taeniasis is often asymptomatic, but the ingestion of larvae can cause abdominal discomfort, nausea, and constipation or diarrhea. Taenia/Taeniasis solium eggs. Cysts can form anywhere in the CNS and cause personality changes, 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, focal neurologic deficits, or signs of intracranial hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension. The diagnosis is usually made based on the “swiss cheese” appearance of the brain on MRI or CT. Serology may also be useful. Management is controversial, but may include steroids, anthelmintic therapy, and neurosurgical consultation.
  • Intracranial tumors: a benign or malignant growth of cells in the brain that present as headache, unexplained nausea or vomiting, blurred vision, and difficulty in speech or hearing. The diagnosis is made with a neurologic examination, imaging (MRI or CT), and, sometimes, biopsy. Management includes radiation, chemotherapy, and/or surgery.
  • Brain abscess Brain abscess Brain abscess is a life-threatening condition that involves the collection of pus in the brain parenchyma caused by infection from bacteria, fungi, parasites, or protozoa. The most common presentation is headache, fever with chills, seizures, and neurological deficits. Brain Abscess: a collection of pus in the brain parenchyma due to an infection. A brain abscess presents with fever, 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, nausea, and vomiting. The diagnosis is mainly based on imaging, as it is difficult to arrive at a definitive diagnosis based on clinical presentation alone. Management includes antibiotic therapy and surgery to drain the abscess.

References

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  3. Guerina, N.G., Marquez, L. (2020). Congenital toxoplasmosis: Clinical features and diagnosis. In Armsby, C. (Ed.), UpToDate. Retrieved April 22, 2021, from https://www.uptodate.com/contents/congenital-toxoplasmosis-clinical-features-and-diagnosis
  4. Gandhi, R.T. (2021). Toxoplasmosis in patients with HIV. In Mitty, J. (Ed.), UpToDate. Retrieved April 22, 2021, from https://www.uptodate.com/contents/toxoplasmosis-in-patients-with-hiv
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