EVALUATION OF THE RANGE OF CLINICAL PRESENTATIONS OF HERPES-SIMPLEX ENCEPHALITIS BY USING POLYMERASE CHAIN-REACTION ASSAY OF CEREBROSPINAL-FLUID SAMPLES

Detection of DNA from herpes simplex virus in cerebrospinal fluid (CSF ) samples by polymerase chain reaction (PCR) analysis has been shown t o be more sensitive and specific for the diagnosis of herpes simplex e ncephalitis than isolation of herpes simplex virus from biopsy specime ns of brain tissue. Because of the invasiveness of brain biopsy, it ha s been suggested that PCR analysis of CSF may reveal a wider spectrum of the disease than has been previously recognized by brain biopsy stu dies. In this study, PCR assay of CSF samples obtained from 29, 12, an d 8 patients with focal, mild, and diffuse encephalitis, respectively, was performed. PCR assay was positive for 15 (51.7%) of 29 patients w ith focal encephalitis and three (25%) of 12 patients with mild enceph alitis. The correlation between temporal abnormalities shown by electr oencephalography, computed tomography of the brain, or cranial magneti c resonance imaging and a positive PCR assay was high. PCR analysis ha s revealed that atypical and less severe forms of encephalitis are cau sed by herpes simplex virus.