Toxoplasmosis is an infection with the parasite Toxoplasma gondii, caught from undercooked meat, soil or cat feces. Healthy people often have mild or no symptoms, but it can cause brain lesions in people with weak immune systems and harm a baby infected during pregnancy.
Key symptoms
- Often none, or a mild flu-like illness
- Swollen lymph nodes, mostly in the neck
- In advanced HIV: headache, confusion, fever, one-sided weakness or seizures
- Blurred vision or floaters from eye infection
What you find on exam
- Painless, firm lymph nodes
- Focal neurologic deficits and mental status changes
- Eye exam: retinal inflammation and scars
- In newborns: abnormal head size, jaundice, large liver and spleen
Tests
- Toxoplasma IgG and IgM antibodies
- In HIV: CD4 count and brain MRI, which shows multiple ring-enhancing lesions
- In pregnancy: avidity testing to date the infection and PCR of amniotic fluid
- Brain biopsy or response to treatment if the diagnosis is unclear
Treatment basics
- Healthy patients with mild illness: usually no treatment
- Brain or eye disease: pyrimethamine plus sulfadiazine with leucovorin
- Trimethoprim-sulfamethoxazole as an alternative, and as prevention when CD4 is below 100
- Pregnancy: spiramycin or pyrimethamine-based therapy guided by a specialist
- Start antiretroviral therapy in HIV; teach food and cat litter safety
Red flags
- New seizure, confusion or weakness in someone with HIV
- Sudden vision loss or eye pain
- New infection during pregnancy
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.