Download Viral Encephalitis

Viral Encephalitis
29/10/10
UptoDate
-
viral infection of the brain parenchyma
acute encephalitis: HSV 1 + 2, enterovirus, VZV, CMV
post infectious encephalitis: mumps, measles, VZV, rubella, influenza
often there is an overlap with meningtitis
CLINICAL FEATURES
- brain function abnormal:
-> altered mental status (confused, agitated, obtunded)
-> motor and sensory deficits
-> altered behaviour
-> personality changes
-> speech disorders
-> movement disorders
-> seizures
-> hemiparesis
-> cranial nerve palsies
-> exaggerated deep tendon reflexes
- meningitis: headache, uncomfortable and lethargic (but normal brain function)
- post-infectious encephalitis = acute disseminated encephalomyelitis (ADEM)
INVESTIGATIONS
CT – good to rule out space occupying lesion
MRI
-> temporal lobe – HSV
-> basal ganglia, thalmi, mesial temporal structures – West Nile
-> hydrocephalus – bacterial, fungal, parasite
EEG – often abnormal, temporal lobe – HSV
CSF
-> WCC elevated, lymphocytes, less than 250
-> elevated protein
-> normal or moderately low glucose
CSF PCR – HSV 1 and 2, CMV, VZV, enterovirus
Brain biopsy – last resort
Jeremy Fernando (2011)
MANAGEMENT
Empiric Treatment
- acyclovir 10mg/kg Q8hrly
- ceftriaxone 1-4g IV OD
PROGNOSIS
HSV encephalitis – 1 year mortality even with treatment 14%, 25% have epilepsy or
neuropsychiatric sequelae
Jeremy Fernando (2011)