Virology USMLE Step 1 Practice Question
A 28-year-old man with HIV/AIDS (CD4 count 45 cells/μL) presents with progressive cognitive decline, headache, and focal neurological deficits over two weeks. Vital signs: BP 118/76, HR 92, RR 16, Temp 37.2°C, SpO2 98% on room air. MRI reveals multiple ring-enhancing lesions in basal ganglia and white matter with surrounding edema. CSF protein is elevated at 85 mg/dL. No fever noted. Which organism most likely explains these findings?
Answer choices
- AMycobacterium avium complex
- BToxoplasma gondiiCorrect answer
- CCytomegalovirus
- DAspergillus fumigatus
- ECryptococcus neoformans
- FPrimary CNS lymphoma (PCNSL)
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