Fact-sheet: Herpes Virux Simplex encephalitis - HSV


Updated on 04/22/2020 at 10:17 AM

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Definition

Encephalitis caused by HSV1 or HSV2.

Setting:

  • In adults, viral reactivation
  • In children, primary infection.

Clinical features

  • Febrile confusion: disorientation, hallucinations, behavioral disturbances, aphasia
  • Febrile headache
  • Olfactory abnormalities: cacosmia
  • Seizures
  • Deficit syndrome
  • Febrile coma

Laboratory findings

Lumbar puncture:

  • Lymphocytic meningitis with normal glucose.
  • HSV PCR, may be negative during the first 4 days.

CT

  • Internal temporal hypodensity, initially unilateral then possibly becoming bilateral, followed by frontal and insular involvement. Appearance delayed by 3 to 5 days relative to initial signs.

MRI

Reference examination, positive early.
Location: temporal lobes (hippocampus, insula) then cingulate gyrus and frontal lobes

  • T2: cortico-subcortical hyperintensity in the temporal lobes with mass effect
  • Diffusion: hyperintense lesion (cytotoxic edema)
  • T1 hypointensity.
  • Coronal FLAIR of interest.
  • T2*: frequent small hemorrhagic areas

Management

Treatment with IV Acyclovir for 3 weeks.
Nephrological monitoring due to the risk of crystallization.

EEG: may show slow discharges in the temporal region, not urgent.