Long-term neurological outcome in patients presenting with encephalitis.

Background: Advances in encephalitis research have improved the definition and management of encephalitis during the acute phase. Still, little is known about long-term outcomes in different subtypes of encephalitis.

Objectives: To analyze the prevalence and predictors of long-term clinical outcomes in different subtypes of encephalitis.

Methods: All patients discharged from a tertiary hub for acute neurology with a confirmed diagnosis of encephalitis were included. Encephalitis were classified into autoimmune (AE), infectious (IE) and of unknown origin (UE) according to guidelines. Long-term neurological sequelae were evaluated using a 16-item questionnaire assessing severity and frequency of neurological symptoms, disability was scored using the expanded Disability status scale (EDSS). Long-term symptoms distribution and predictors were evaluated using univariate and multivariate regression models.

Results: Seventy out 105 survived patients were included (AE n = 30, IE n = 12, UE n = 28). Disability at discharge was worse in AE compared to UE (p = 0.018). Additionally, AE had a higher risk of relapse (n = 8 AE, n = 1 UE, p = 0.001). 36 patients (51,4%) showed significant disability according to EDSS; whereas 72,9% reported a significant neurological long-term sequela, including cognitive deficits (50,0%), depression (41,4%) and numbness (21,0%). Older age and abnormal MRI at onset were the strongest predictors of long-term severe sequelae. independently from the subtype of encephalitis.

Discussions: Long-term sequelae are common in encephalitis, and are associated with MRI abnormalities, premorbid disability, and older age at onset. Further longitudinal studies are needed to focus on biological and clinical predictors, to identify patients who might benefit from cognitive and behavioral training after discharge.