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QUESTION1. PRESENTATION: Toxoplasmosis - immunosuppressed patients (HIV, pregnancy) with undiagnosed lymphadenopathy or any granulomatous uveitis or retinitis. 2. Symptomatic acquired toxoplasmosis resembles infectious mononucleosis, and is usually self-limiting. 3. Congenital eye infection presents with posterior uveitis and may cause cataract.4. EPIDEMIOLOGY: most infections are asymptomatic - in the UK >50% are infected by 70yrs.  5. COMPLICATIONS: In the immunocompromised (e.g. AIDS) - myocarditis, encephalitis, brain lesions, stroke or seizures.

Neurology

QUESTION1. PRESENTATION: Toxoplasmosis - immunosuppressed patients (HIV, pregnancy) with undiagnosed lymphadenopathy or any granulomatous uveitis or retinitis. 2. Symptomatic acquired toxoplasmosis resembles infectious mononucleosis, and is usually self-limiting. 3. Congenital eye infection presents with posterior uveitis and may cause cataract.4. EPIDEMIOLOGY: most infections are asymptomatic - in the UK >50% are infected by 70yrs.  5. COMPLICATIONS: In the immunocompromised (e.g. AIDS) - myocarditis, encephalitis, brain lesions, stroke or seizures.

ANSWER
1. AIDS-related brain lesions: If you see multiple ring-enhancing lesions, think toxoplasmosis. (CNS lymphoma, TB, and bacterial infections are less likely)

2. Toxoplasma IgM: acute infection is confirmed by a 4-fold rise in antibody titre over 4wks or specific IgM (unreliable if HIV +ve).

3. Toxoplasma IgG: because toxo is a reactivation infection, patients typically have IgG (but not IgM) antibody to T gondii.

4. CNS Biopsy: do a brain biopsy if there is no improvement after empiric treatment, if there is a mass effect, or if there is only 1 lesion.

5. Some empirically treat single lesions if the CD4 count is < 100 and the patient hasn't been on toxo prophylaxis. Relapses occur often.


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REFERENCES

1. Wilkinson, I. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press.
2. Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
3. Image: no reference available.

Ⓒ A. Manickam 2018

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