Management and outcome predictors during Herpes simplex virus encephalitis

Background: Herpes simplex virus encephalitis (HSE) is the most common cause of sporadic acute viral encephalitis in adults associated with a high incidence of severe and permanent neurologic sequelae. We aimed to identify the epidemiological, clinical, evolutionary features and to study the outcome predictors of HSE.Methods: We carried out a retrospective study including all patients hospitalized for HSE in the infectious diseases department between January 1994 and December 2018.Results: We encountered 30 patients with HSE, among whom 15 patients were male (50%). The mean age was 44±16 years. The most common clinical features were fever (96.6%), cephalalgia (70%) and aggressive behaviour (63.3%). Analysis of cerebrospinal fluid (CSF) revealed an elevated white blood cell (WBC) count (86.6%) with lymphocyte-predominant pleocytosis (96.1%). Herpes simplex virus (HSV) PCR assay in the CSF was positive in 73.3% of the cases. Brain computed tomography scan demonstrated parenchymal hypodensity (66.6%), while brain magnetic resonance imaging (MRI) was pathological (88.8%). Temporal involvement was characteristic in 66.6% of the cases. All patients received intravenous acyclovir for a mean duration of 19±7 days. There were 17 cases with a favourable prognosis (56.6%). Comparison of the disease evolution showed that poor prognosis was significantly more frequent in patients hospitalized after a delay of 3 days after the onset of symptoms [odds ratio (OR) =13.5 (1.4–80.2); P=0.017], in patients presenting hemiparesis (P=0.02) and when hypoglycorrhachia was noted [OR =10.5 (1.8–58.3); P=0.008]. Starting acyclovir therapy after a delay of 3 days was significantly more associated with a poor prognosis [OR =10.6 (1.2–74.3); P=0.04].Conclusions: Our study highlighted the burden of HSE which remains a fatal, life threatening disease associated with a poor prognosis and neurological sequelae especially when the diagnosis and the treatment were delayed.