To biopsy or not to biopsy in suspected herpes simplex encephalitis: a quantitative analysis.

The authors performed a decision analysis to determine whether a patient suspected to have herpes simplex encephalitis (HSE) should undergo a brain biopsy or be treated empirically with medical therapy. In most cases, empiric treatment with acyclovir would be slightly favored; brain biopsy was not essential in management. However, brain biopsy was found useful for patients who had low CSF glucose at the time of initial lumbar puncture; such patients may have a very high risk to have other treatable conditions such as tuberculosis, brain abscess, toxoplasmosis, or cryptococcosis. The results of the analysis suggest that even with the advent of safe antiviral drug therapy such as acyclovir, brain biopsy is useful in a well-defined subset of patients with possible HSE. The rationale, however, is not to confirm HSE but rather to detect other treatable conditions.