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NMOSD – Satralizumab Mechanism — SCE Neurology MCQ

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HardMultiple Sclerosis & CNS InflammationNMOSD – Satralizumab MechanismSCE Neurology

A 48-year-old has fever, focal seizures and new dysphasia. MRI shows right temporal diffusion restriction and CSF has a lymphocytic pleocytosis with red cells. HSV PCR from a lumbar puncture performed 18 hours after symptom onset is negative. What is the best immediate plan?

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Correct answer: C — Continue aciclovir and repeat CSF HSV PCR

Explanation lettering: C = shown as A · D = shown as B · E = shown as C · A = shown as D · B = shown as E

E is correct: an early HSV PCR can be falsely negative, and the clinical, MRI and CSF pattern remains strongly suggestive of HSV encephalitis. Intravenous aciclovir should continue while CSF PCR is repeated after an appropriate interval and alternative infectious and autoimmune causes are investigated in parallel. Stopping antiviral treatment on one very early result risks catastrophic undertreatment. Oral therapy is inadequate. Steroids alone are unsafe before infection is controlled, and brain biopsy is reserved for persistently unexplained, treatment-refractory inflammatory disease or suspected malignancy.

Reference: Suspected encephalitis in adults: https://pn.bmj.com/content/early/2026/06/03/pn-2024-004299