Objective: To investigate the clinical characteristics of herpes simplex encephalitis (HSE) and to discuss the mechanism of its relapse.
Method: The clinical data of 6 patients with relapsing encephalitis, 4 male and 1 female, aged 14 - 49, out of 150 encephalitis cases were analyzed: 5 of them were suspected as with HSE clinically, and HSE was confirmed by pathology via biopsy in 2 of the 6 patients. The 5 patients were followed up for 2 - 6 years.
Result: The duration between the onset and relapse was 1 - 26 months. Brain MRI or CT showed new lesions in the temporal lobe in 5 patients. Necropsy revealed intracellular inclusions, positive in HSV-1 antigen, in the neurons and glial cells of temporal lobe in one case. Second course of acyclovir therapy was effective in 5 of these 6 patients. One patient died 10 months later.
Conclusion: Direct invasion of activated virus into the central nervous system and insufficiency of acyclovir treatment are the causes of relapse of HSE. Acyclovir treatment should be early, with sufficient amount, and individualized.