Clinical characteristics and exploratory factors associated with in-hospital mortality in pediatric severe viral encephalitis.

Objective: The aim of this study was to describe the clinical characteristics of severe viral encephalitis (SVE) in children and to identify exploratory factors associated with in-hospital mortality, thereby providing preliminary evidence to facilitate early risk stratification and reduce SVE-related disability and mortality. Methods: A retrospective study was conducted in 75 children diagnosed with viral encephalitis at the Department of Pediatrics, Anqing Municipal Hospital, from January 2023 to December 2025, including 50 mild cases and 25 SVE cases. Demographic data, clinical manifestations, and laboratory parameters (peripheral white blood cell count (WBC), serum sodium, cerebrospinal fluid (CSF) leukocyte and protein levels, serum neuron-specific enolase (NSE), electroencephalography (EEG), neuroimaging findings, and Glasgow Coma Scale (GCS) scores) were collected and compared between groups. Pathogen detection was conducted through multiplex PCR and/or serum viral IgM antibody testing. In the mild encephalitis group, 14 out of 50 cases (28%) were found to be infected with specific viruses, with enteroviruses (EVs) being the predominant type, accounting for 7 cases, followed by herpes zoster virus (VZV) and human herpesvirus type 6 (HHV-6), each with 2 cases. In the SVE group, 9 out of 25 cases (36%) were found to have pathogens, with influenza A virus (4 cases) and herpes simplex virus (2 cases) being the main ones. Univariate analyses and Firth-penalized logistic regression were used to explore factors associated with in-hospital mortality (primary outcome) within the SVE subgroup. Results: Among the 25 children with SVE (15 males, mean age 7.74 ± 2.2 years), fever (76%), signs of elevated intracranial pressure (68%), and seizures (56%) were common; four patients died (16%). Compared with children with mild encephalitis, the SVE group exhibited significantly longer hospital stays, higher seizure rates, lower GCS scores, higher proportions of abnormal EEG and neuroimaging abnormalities, and elevated serum NSE (all Conclusion: Pediatric SVE presents with nonspecific early symptoms and substantial mortality. Seizures, EEG and neuroimaging abnormalities, low GCS score, and elevated serum NSE are exploratory factors associated with in-hospital mortality. However, given the small sample size and single-center design, these findings are hypothesis-generating and require validation in larger multi-center prospective cohorts. Early recognition of these factors may aid in clinical risk assessment.