Abstract
Objective: NA
Background: Herpes simplex virus type 2 (HSV-2) is a rare cause of encephalitis in adults, accounting for perhaps 2% of all herpes simplex encephalitis (HSE) cases. HSV-2 encephalitis typically occurs in elderly, immunosuppressed patients and is associated with high rates of death and long-term neurologic sequelae.
Design/Methods: NA
Results: A previously healthy 71 year old male presented with three days of left-sided headache, word-finding difficulties, and short-term memory loss. He had a syncopal event at time of presentation and was admitted to the hospital. Initial workup including labs and head CT were notable for a serum sodium of 126 and negative HIV testing. Brain MRI with contrast was interpreted as normal. Twelve hours into hospitalization he fevered, leading to a lumbar puncture and initiation of empiric acyclovir therapy. Cerebrospinal fluid studies showed 42 WBC’s, 1 RBC, normal protein at 42, and elevated glucose at 74. Meningoencephalitis PCR panel was positive for HSV-2. When the neurology consultants reviewed his brain MRI, they noted previously unrecognized subtle T2 hyperintensities in the left insular and orbitofrontal regions. Repeat brain MRI five days later showed worsening T2 signal in these areas, along with extension to the anterior left temporal lobe and medial right temporal lobe. The patient was treated with intravenous acyclovir for 21 days but had persistent language and cognitive difficulties at three month follow-up.
Conclusions: Despite classic teaching, HSV-2 encephalitis does occur in immunocompetent adults. While similar to HSV-1 encephalitis in many respects, it may present without fever and with normal imaging or only very subtle imaging abnormalities. Patients thought to have viral encephalitis, but with normal imaging or negative CSF HSV-1 PCR, should also have CSF HSV-2 PCR performed. Because untreated HSE carries with it a 70% mortality rate, neurologists should maintain a high level of clinical suspicion in such cases.
Study Supported by:
Disclosure: Dr. Cook has nothing to disclose. Dr. Koehn has nothing to disclose. Dr. Simmons has nothing to disclose. Dr. Frattalone has nothing to disclose.
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