A retrospective analysis of forty-six cases of herpes simplex encephalitis seen in Glasgow between 1962 and 1985.

The clinical features, investigative profiles and outcome of 46 patients with biopsy or autopsy-proven herpes simplex encephalitis admitted to the Institute of Neurological Sciences, Glasgow between 1962 and 1985 were analysed retrospectively. The protean presenting symptoms and signs included a history of a prodromal influenza-like illness (48 per cent), rapid onset of headache, clouding of consciousness and confusion (52 per cent), meningism (65 per cent), raised intracranial pressure (33 per cent), deep coma (35 per cent), mutism or aphasia (46 per cent), focal neurological signs (89 per cent), and seizures (61 per cent). When seizures occurred they were almost always focal. The electroencephalogram was the most useful diagnostic test being abnormal in all cases, the majority showing focal changes in one or other hemisphere. Of the neuroradiological procedures employed, computerized tomographic and isotope brain scanning most frequently demonstrated localizing abnormalities in one or both temporal and/or frontal lobes. Midline shift was seen in half the cases. The cerebrospinal fluid was abnormal in every case but was not diagnostic. Cerebral biopsy of one temporal lobe was performed in 40 cases and a positive diagnosis of acute necrotizing encephalitis was made in 37 of these. Herpes simplex virus was isolated from the brains of 29 of the 40 cases in which the procedure was attempted, but immunofluorescence assays for antigens to herpes simplex virus were only positive in 11 out of 25 cases. Serological assays showed a greater than four-fold rise in the anti-herpes simplex virus antibody titre in 13 out of 22 patients tested.(ABSTRACT TRUNCATED AT 250 WORDS)