Vital Prognosis and Causes of Death in Adults with Encephalitis.

backgroundEncephalitis in adults is associated with inpatient mortality in approximately 10% of patients, but the cause and timing of death are unknown.

methodsWe conducted a retrospective study across two tertiary healthcare systems in Texas and Maryland between 2002 and 2023. Adults hospitalized with all-cause encephalitis were included. Our primary outcome was inpatient death. We investigated the association of various factors with mortality. The causes of death were categorized into three groups: category 1, where encephalitis was the direct cause of death; category 2, the underlying cause contributing to mortality but not directly responsible; or category 3, unrelated to the cause of death, acting independently. We subsequently examined the timing of death from initial presentation.

resultsA total of 629 adults with encephalitis were enrolled, 45 (7.15%) of whom died inpatient. In the cohort of 243 patients admitted to the intensive care unit (ICU), 41 deaths occurred, corresponding to a mortality rate of 16.87%. Logistic regression analysis identified body mass index (BMI), presence of comorbidities [Charlson Comorbidity Index (CCI] score], immunocompromise, memory deficits, elevated Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, altered mental status [Glasgow Coma Scale (GCS) score < 8], thrombocytopenia, hypoglycorrhachia, arrythmias, and ICU admission as significant predictors of mortality (p < 0.001 after Bonferroni correction). When restricting the analysis to patients admitted to the ICU, CCI score, psychiatric manifestations, memory deficits, and GCS retained statistical significance (p < 0.05). Encephalitis was the direct cause of death (category I) in 66% of cases with a median time to death of 12 days, the underlying cause (category 2) in 27% with a median of 14 days, and unrelated (category 3) in 7% within a median of 43 days. As for timing of death, 22% and 53% died in the first 7 and 14 days, respectively.

conclusionAll-cause encephalitis is associated with a low mortality rate of 7.15%, but higher among patients requiring ICU admission (16.87%). Among fatal cases, encephalitis was the direct or underlying cause of death in more than 90% of cases, with the majority of deaths occurring in the first 2 weeks.