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HSV encephalitis — RACP Paediatrics MCQ

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ModerateNeurologyHSV encephalitisRACP Paediatrics

A 7-year-old presents with 3 days of fever followed by acute onset confusion, personality change, and seizures. MRI brain shows signal abnormality in the temporal lobes bilaterally. CSF shows lymphocytic pleocytosis with elevated protein and normal glucose. What is the most likely diagnosis?

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Correct answer: B — Viral encephalitis (HSV)

Acute encephalitis with fever, personality change, seizures, and bilateral temporal lobe abnormality on MRI with lymphocytic CSF pleocytosis is highly suggestive of HSV encephalitis. IV aciclovir (at meningitic doses) must be started immediately and should not be delayed pending PCR results. HSV PCR may be negative in the first 24-72 hours.

Reference: RCH Melbourne – 2023 – Encephalitis CPG; Australian Therapeutic Guidelines – 2024