Demyelinating Diseases USMLE Step 1 Practice Question
A 24-year-old man presents with 5-day progressive fever (38.9°C), headache, and altered mental status. Vital signs show HR 102, BP 128/76, RR 18, SpO2 98% on room air. Brain MRI demonstrates bilateral temporal lobe T2/FLAIR hyperintensity with enhancement and periventricular white matter lesions. CSF analysis reveals lymphocytic pleocytosis (68 cells/μL), normal glucose (55 mg/dL), and negative HSV-1 PCR. He denies recent vaccinations. Which of the following is most likely?
Answer choices
- AHerpes simplex encephalitis
- BAnti-NMDA receptor encephalitisCorrect answer
- CMultiple sclerosis with superimposed infection
- DBacterial meningitis
- EAcute demyelinating encephalitis
- FLimbic encephalitis associated with voltage-gated potassium channel antibodies
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