When should a diagnosis of herpes simplex encephalitis (HSE) be considered in the ED and how should it be managed?

Updated: Jul 17, 2018
  • Author: Wayne E Anderson, DO, FAHS, FAAN; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
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A high index of suspicion is required to make the diagnosis of herpes simplex encephalitis (HSE), and expeditious evaluation is indicated after the diagnosis is considered. In the absence of any other identifiable cause, consider HSE in any febrile patient with encephalopathy and CSF pleocytosis. Start empiric acyclovir therapy promptly in patients with suspected HSE pending confirmation of the diagnosis because acyclovir, the drug of choice, is relatively nontoxic and because the prognosis for untreated HSE is poor.

Failure to consider the possibility of HSE can result in delayed diagnosis and treatment, with subsequent increased risks of mortality and morbidity. A single-center study from a high-volume academic emergency department (ED) reported that only 29% of patients with a presentation suggestive of viral encephalitis (fever, neuropsychiatric abnormalities, cerebrospinal fluid [CSF] pleocytosis, and a negative CSF Gram stain) received acyclovir in the ED. [40]

See the following for more information:

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