Focal neurological lesions

Toxoplasmosis

• accounts for around 50% of cerebral lesions in patients with HIV
• constitutional symptoms, headache, confusion, drowsiness
• CT: usually single or multiple ring enhancing lesions, mass effect may be seen
• management: sulfadiazine and pyrimethamine

MRI with gadolinium. Multiple ring-enhancing lesions in the deep periventricular area consistent with cerebral toxoplasmosis - e Image used on license from Radiopaedia

Toxoplasmosis

Toxoplasma gondii is an obligate intracellular protozoan that infects the body via the gastrointestinal tract, lung or broken skin. It's oocysts release trophozoites which migrate widely around the body including to the eye, brain and muscle. The usual animal reservoir is the cat, although other animals such as rats carry the disease.

Usually asymptomatic or self-limiting minor illness in immunocompetent people.

Serology is the investigation of choice.

No treatment is usually required unless the patient has a severe infection or is immunosuppressed.

Cerebral toxoplasmosis accounts for around 50% of cerebral lesions in patients with HIV

• constitutional symptoms, headache, confusion, drowsiness
• CT: usually single or multiple ring-enhancing lesions, mass effect may be seen
• management: pyrimethamine plus sulphadiazinefor at least 6 weeks

Immunosuppressed patients may also develop a chorioretinitis secondary to toxoplasmosis.