Herpes simplex encephalitis cases with typical and atypical symptoms confirmed by PCR-amplification of the DNA polymerase gene

Objective: We have confirmed by PCR-amplification of the DNA polymerase gene, three cases of Herpes Sim- plex encephalitis (HSE) with atypical clinical symp- toms. Methods: Cerebrospinal fluid (CSF) samples were col- lected by lumbar puncture during the course of test- ing from 23 patients suspected to have viral encepha- litis based on commonly encountered symptoms, cy- tochemical analysis and neurological testing. PCR was done on CSF using specific primers that amplify a 290 base pair sequence on the DNA polymerase gene com- mon to both HSV-1 and HSV-2 strains. Results: Only 3 of the 23 CSF samples collected showed the expected amplicon size on the target se- quence. One case had conventional symptoms of en- cephalitis and 2 cases showed atypical symptoms from the conventional ones. All 3 patients recovered after administration of acyclovir. Fourteen PCR-negative patients were shown to have non-HSE viral encephali- tis and the remaining 6 patients were shown later to have other neurological diseases. Conclusion: PCR was efficient in elucidating the atypi- cal cases of HSV encephalitis.