Severe encephalitis: aetiology, management and outcomes over 10 years in a paediatric intensive care unit.

OBJECTIVE: To describe the characteristics, differential diagnoses, management and outcomes of severe encephalitis in children. DESIGN: A 10-year retrospective cohort study in children admitted to a tertiary paediatric intensive care unit (PICU) with suspected encephalitis. One to 6 months' follow-up data were compared between different categories. PARTICIPANTS: Patients from 0 to 17 years of age with acute encephalopathy and one or more of fever, seizure, focal neurological findings, cerebrospinal fluid abnormalities, EEG/neuroimaging consistent with encephalitis. MAIN OUTCOME MEASURES: Epidemiology, clinical features, outcomes and risk factor analysis. RESULTS: 175 children with encephalitis required intensive care unit (ICU) admission over 10 years. The median age was 4.5 months (IQR 1.6-54.8). The leading cause was enterovirus (n=49, 28%), followed by parechovirus, influenza, herpes simplex virus (HSV), human herpesvirus-6 (HHV-6), Streptococcus pneumoniae, acute-disseminated encephalomyelitis and anti-N-methyl-D-aspartate-receptor-associated encephalitis. Immune-mediated encephalitis had higher prevalence in females, older age and longer duration of encephalopathy. Mechanical ventilation was required by 74 children (42%); haemodynamic support by 28 children (16%), 3 received extracorporeal membrane oxygenation (ECMO) support. Eleven patients died (case fatality rate 6.3%): five with HHV-6, two enterovirus, two influenza, one HSV, one human-metapneumovirus. At follow-up, 34 children had mild or moderate disability, and six severe disability. In a multivariable logistic regression model, three factors were associated with severe disability or death: age <2 years old (OR 8.2, CI 1.0 to 67.2), Herpesviridae aetiology (OR 14.5, CI 1.2 to 177.3) and length of intubation (OR 1.005, CI 1.00 to 1.01). CONCLUSIONS: Encephalitis has a varied aetiology and causes death or severe disability in 1 in every 10 children requiring intensive care.