High Yield Review - Herpes Simplex Virus (HSV) Encephalitis:
Case: A 30 year old female brought in by ambulance,
with a witnessed seizure. She is altered in mentation ,
she is febrile and tachycardic. CT Head w/o contrast shows
no acute abnormality. A lumbar puncture is performed
and CSF analysis shows; normal opening pressure, normal glucose, Elevated Protein, WBC of 300 , and > 50% Lymphocytes. An HSV PCR on CSF was collected and is initially negative. A FLAIR MRI was performed --> b/l temporal lobe and frontal lobe involvement.
She was started on Acyclovir 10mg/kg q8 for 21 days.
Case Clues - HSV Encephalitis:
- Altered + Fever + Seizures
- CSF --> Shows Lymphocytic Pleocytosis
- HSV PCR was initially negative
- MRI Findings in the temporal and frontal lobes
Know it for the boards - HSV Encephalitis!
- Most common presentation: Altered mental status , fever, and seizures ( or neuro abnormalities )
- CSF: Lymphocytic Pleocytosis
- FLAIR MRI: Most sensitive and specific will see Temporal and Frontal Lobe abnormalities
- HSV PCR Can initially be negative, but then positive on repeat LP
- Treat with Acyclovir 10mg/kg Q8 X 21 Days
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