Toxoplasmosis

Case history #1

A 45-year-old man with HIV (CD4+ T lymphocyte count 55 cells/microlitre) and poor medical follow-up presents with fever, confusion, right hemiplegia, and slurred speech. He is taking no medications. A computed tomography scan with intravenous contrast of the head reveals multiple ring-enhancing lesions with surrounding vasogenic oedema. Ophthalmological examination reveals retinitis. Cerebrospinal fluid bacterial antigen panel is negative and serum has detectable anti-Toxoplasma immunoglobulin (Ig) G.

Case history #2

A 25-year-old woman in her third trimester of pregnancy is found to have positive serology for anti-Toxoplasma IgG. No previous serological profiles are available. She reports no recent illnesses, and has no significant medical history. She reports taking care of several cats at home, and frequently changes their litter. Her physician then checks for anti-Toxoplasma IgM, which is positive. Sonogram of the fetus shows no abnormalities.

Other presentations

Symptomatic disease can manifest itself as cervical or occipital lymphadenopathy with or without fever, or as ocular chorioretinitis.

Atypical presentations include transverse myelitis, polymyositis, myocarditis, pneumonitis or disseminated disease with fever, and bone marrow suppression. Myocarditis can present as chest pain and heart failure and can be mistaken for myocardial infarction. It may also present with pericarditis, arrhythmias, heart block, or sudden death. Myocarditis can occur as re-activation of disease in people who are immunocompromised (because of AIDS, solid organ/haematopoietic stem cell transplants, or systemic lupus erythematosus) or during primary infection, even (rarely) in those with intact immune systems. Anaemia, haemophagocytic syndrome, and/or peripheral neuropathy may also result from toxoplasmosis.

Symptomatic disease, aside from congenital toxoplasmosis, is rare without severe immune suppression.

Toxoplasmosis should be highly suspected in any patient who is severely immunosuppressed with ring-enhancing brain lesions on computed tomography/magnetic resonance imaging, or in women during pregnancy with documented seroconversion.