Today we discussed the case of a young male in his twenties who presented with a prodrome of confusion and lethargy. Based on new onset seizures, fever and a non-purulent LP the demographics and presentation were highly suggestive of HSV encephalitis…
HSV Encephalitis:
· worldwide the most common cause of sporadic fatal encephalitis
· although occurring in all age groups – approx. 1/3 of people are children / adolescents
· almost always HSV-1 (vs HSV-2 which is a more common cause encephalitis in neonates)
· rarely in the context of skin disease / outbreaks
clinical presentation: clinical syndrome is often characterized by rapid onset of fever, headache, seizures, focal neurological signs of <>diagnosis: LP may show nothing or more commonly lymphocytic pleocytosis, increased RBC and protein. uncommon to have a low glucose. LP should be sent for HSV PCR (sensitivity = 98%, specificity = 94-100%). alternatives include brain biopsy of temporal lobe. viral cultures rarely positive.
iamging may show temporal lobe abnormalities (50% sensitivity of CT brain – MRI more sensitive and specific but can be negative). Non-specific EEG findings are noted in 80% of patients.
treatment: early empiric treatment is a priority - iv acyclovir is the treatment of choice
prognosis: if untreated mortality is 70%; even with early treatment up to 2/3 will have residual deficits
differential diagnosis: viral encephalitis (e.g. HIV, west nile), brain tumour, subacute sclerosing panencephalitis, neurosyphillis, post infectious (e.g. Reye’s), acute disseminated encephalomyelitis, other (SLE, subdural, intracerebral bleeding, adrenal leukodystrophy)
· worldwide the most common cause of sporadic fatal encephalitis
· although occurring in all age groups – approx. 1/3 of people are children / adolescents
· almost always HSV-1 (vs HSV-2 which is a more common cause encephalitis in neonates)
· rarely in the context of skin disease / outbreaks
clinical presentation: clinical syndrome is often characterized by rapid onset of fever, headache, seizures, focal neurological signs of <>diagnosis: LP may show nothing or more commonly lymphocytic pleocytosis, increased RBC and protein. uncommon to have a low glucose. LP should be sent for HSV PCR (sensitivity = 98%, specificity = 94-100%). alternatives include brain biopsy of temporal lobe. viral cultures rarely positive.
iamging may show temporal lobe abnormalities (50% sensitivity of CT brain – MRI more sensitive and specific but can be negative). Non-specific EEG findings are noted in 80% of patients.
treatment: early empiric treatment is a priority - iv acyclovir is the treatment of choice
prognosis: if untreated mortality is 70%; even with early treatment up to 2/3 will have residual deficits
differential diagnosis: viral encephalitis (e.g. HIV, west nile), brain tumour, subacute sclerosing panencephalitis, neurosyphillis, post infectious (e.g. Reye’s), acute disseminated encephalomyelitis, other (SLE, subdural, intracerebral bleeding, adrenal leukodystrophy)
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