ENCEPHALITIS

 

Etiology:

  1. Viruses: herpes simplex, arboviruses, rabies

S & S: 

  1. Similar to meningitis (AMS, SZ, HA, vomiting, fever, lethargy). Onset is somewhat abrupt. This description while more specific to HSV, can differ form cases of EBV where pt classically   presents with combative behavior, SZ, HA, focal findings.
     
  2. Some have predilection to specific lobes with consequent focal findings.

DX:

  1. CT/MRI ® localized edema to a lobe (subfrontal and temporal lobe are most commonly involved in HSV), patchy hemorrhages.  Neither CT nor MRI are specific or sensitive and findings can be delayed for 5-7 days.
     
  2. LP ( see above).
     
  3. EEG may help localize lesion.

Treatment:

  1. Supportive treatment if viral, except HSV-1 (most common), where Acyclovir 10mg/kg IV q8h x14-21 days is indicated.
     
  2. Other treatments are directed towards causative agents.

 

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