Rapid and accurate diagnosis of herpes simplex encephalitis with computed tomography stereotaxic biopsy.

Four patients with suspected herpes simplex encephalitis underwent cerebral biopsies using a stereotaxic technique coupled with computed tomography (CT) scanning. Typical histopathologic features of viral encephalitis were identified on frozen section, allowing rapid introduction of systemic antiviral therapy. Herpes simplex virus was isolated from cultures from the brain within 24-48 hours. Despite antiviral therapy, three patients died and the fourth patient remains severely neurologically impaired. Treatment was started too late in the clinical course to be effective. To reduce the strikingly high mortality and morbidity associated with herpes simplex encephalitis, a biopsy must be performed as early as possible to confirm the diagnosis or to exclude other treatable conditions. Appropriate antiviral therapy must be predicated on a positive biopsy and instituted immediately after diagnosis. We prefer the CT stereotaxic technique to other biopsy methods because it defines the involved locus in the brain, obviates the need for other time-consuming neurodiagnostic procedures, and provides 1-mm accuracy in reaching the desired biopsy site. Performed early in the clinical course, CT stereotaxic biopsy provides rapid histologic and virologic diagnosis and may eventually reduce the still unacceptably high mortality and morbidity associated with herpes simplex encephalitis.