346. Prognostic Factors in Adults with Encephalitis: An Analysis of 340 Cases

BACKGROUND: Encephalitis continues to be a significant cause of morbidity and mortality with only a few studies assessing prognostic factors. METHODS: A multicenter retrospective review of adults with encephalitis as defined by the international encephalitis consortium between 2000 and 2017 at 19 hospitals in New Orleans, Louisiana, and Houston, Texas. An adverse clinical outcome was defined as a Glasgow outcome scale between 1 and 4. Logistic regression analysis was used to evaluate prognostic factors. RESULTS: A total of 340 adults were enrolled. The mean age was 48 years with 184 (54.1%) being male. Out of 340 patients, 268 (79%) had probable or confirmed encephalitis and 71 (21%) had possible encephalitis. An etiology was documented in 151 cases (44.5%) with the most common etiologies being arboviruses (17%), Herpes simplex virus (HSV)(16.5%), and anti-N-methyl-d-aspartate receptor antibody (13.4%). An adverse clinical outcome was observed in 172 out of 322 (53%) of patients. On bivariate analysis, age >60 years, respiratory failure, intensive care admission, fever, abnormal neurological examination, abnormal electroencephalogram, and abnormal magnetic resonance imaging (MRI) of the brain were associated with an adverse outcome (P < 0.05). On logistic regression, only abnormal neurological examination (odds ratio [OR] 4.310, 95% confidence interval [CI] 1.148–12.508), abnormal MRI of the brain (OR 2.131, 95% CI, 1.016–4.469), and fever (OR 2.127, 95% CI, 1.079–4.194) (all P < 0.05) remained independently associated with an adverse outcome. CONCLUSION: Encephalitis in adults is associated with adverse clinical outcomes in 50% of patients with significant predictors being fever, abnormal neurological examination, and abnormal MRI of the brain. DISCLOSURES: All authors: No reported disclosures.