What are the symptoms of toxoplasmosis?

Symptoms of Toxoplasmosis

Most toxoplasmosis infections are initially asymptomatic, but when symptoms occur they vary dramatically based on whether the infection is congenital, acquired in immunocompetent hosts, or occurs in immunocompromised individuals. 1

Congenital Toxoplasmosis

The majority (70-90%) of infants with congenital toxoplasmosis are asymptomatic at birth, but most will develop late sequelae ranging from months to years later. 1

Symptomatic Newborns Present With Two Patterns:

Generalized disease manifestations include: 1

• Maculopapular rash
• Generalized lymphadenopathy
• Hepatosplenomegaly
• Jaundice
• Hematologic abnormalities (anemia, thrombocytopenia, neutropenia)

Neurologic disease manifestations include: 1

• Hydrocephalus
• Intracerebral calcification
• Microcephaly
• Chorioretinitis
• Seizures

Late Sequelae in Initially Asymptomatic Children:

• Retinitis and visual impairment 1
• Intellectual impairment 1
• Neurologic impairment 1

Acquired Toxoplasmosis in Immunocompetent Hosts

Post-natal toxoplasmosis is most often initially asymptomatic, but when symptoms occur they are frequently nonspecific. 1

Common Symptoms Include: 1

• Malaise
• Fever
• Sore throat
• Myalgia
• Cervical lymphadenopathy
• Mononucleosis-like syndrome with maculopapular rash and hepatosplenomegaly

Severe Disease in Immunocompetent Hosts (Rare but Important):

Recent evidence shows that severe toxoplasmosis can occur in immunocompetent patients, particularly with atypical non-type II strains. 2

Pulmonary involvement (44% of severe cases) presents with: 2

• Pneumonia or pleural effusions (94% of pulmonary cases)
• Respiratory failure (47% of pulmonary cases)

CNS involvement (39% of severe cases) presents with: 2

• Encephalitis (54% of CNS cases)
• Meningitis (13% of CNS cases)
• Focal neurologic findings (24% of CNS cases)
• Cranial nerve palsies (17% of CNS cases)
• Guillain-Barre or Miller Fisher syndrome (7% of CNS cases)

Cardiac involvement (31% of severe cases) presents with: 2

• Myocarditis (75% of cardiac cases)
• Pericarditis (50% of cardiac cases)
• Heart failure and/or cardiogenic shock (19% of cardiac cases)
• Cardiac arrhythmias (22% of cardiac cases)

Toxoplasmosis in HIV-Infected and Immunocompromised Patients

Toxoplasma Encephalitis:

The CDC recommends considering Toxoplasma encephalitis in all HIV-infected children with new neurologic findings. 1

Focal neurological deficits are the most common presentation, though diffuse CNS disease can also occur. 3

Key symptoms include: 1, 3

• Fever
• Reduced alertness
• Seizures
• Variable presentation reflecting either focal or diffuse CNS disease

Ocular Toxoplasmosis:

Isolated ocular toxoplasmosis is rare and usually occurs in association with CNS infection, requiring neurologic examination in all diagnosed cases. 1

Presentation includes: 1

• White retinal lesions with little associated hemorrhage
• Visual loss may be observed initially

Less Common Presentations in HIV-Infected Patients: 1

• Systemic toxoplasmosis
• Pneumonitis
• Hepatitis
• Cardiomyopathy/myocarditis

Critical Clinical Pitfalls

Toxoplasmosis should be considered in the differential diagnosis of immunocompetent patients presenting with severe illness of unclear etiology with pulmonary, cardiac, CNS, or multiorgan involvement, even in the absence of common exposure risk factors or typical manifestations like fever, lymphadenopathy, or chorioretinitis. 2

Fatal outcomes can rarely occur even in immunocompetent patients, making prompt recognition and treatment essential. 2

More than one organ can be involved in 26% of severe cases, requiring comprehensive evaluation. 2