EURopean Study on Encephalitis in Intensive CAre

Inclusion Criteria: * Age ≥ 18 years * non-opposition to participate in the study (or consent if applicable according to local legislation) * Impaired consciousness (altered mentation, stupor, or personality changes) for a duration ≥ 24 h, without obvious explanation * A score on the Glasgow Coma Scale \< or =13 at ICU admission * A Cerebrospinal fluid pleocytosis \> = 5 cell / mm3 * At least 2 of the following : * Fever (≥ 38.0 °C) within 72 hours before or after admission * Generalized or partial seizures non-attributable to pre-existing epilepsy * New onset focal neurological deficit * Parenchymal abnormalities on MRI compatible with AE * EEG alterations compatible with AE. Exclusion Criteria: * CSF or neuroimaging not available (s) or not performed. * febrile encephalopathy associated with another diagnosis (sepsis, neurological disease with aspiration pneumonia ... )