Childhood Encephalitis in Canada in 2015

TABle 1 Diagnostic criteria for encephalitis and encephalopathy of presumed infectious or autoimmune etiology* Major criterion (required) Altered mental status, defined as decreased or altered level of consciousness, lethargy, or personality change lasting 24 h with no alternative cause identified Minor criteria (two for possible encephalitis, 3 for probable or confirmed encephalitis) Documented fever 38.0C (100.4F) within 72 h before or after presentation Generalized or partial seizures not attributable to a pre-existing seizure disorder New onset of focal neurological findings Cerebrospinal fluid pleocytosis (leukocyte count 510 6 /L) Abnormality of brain parenchyma on neuroimaging suggestive of encephalitis that is either new from previous studies or appears to be acute in onset Abnormality on electroencephalography that is consistent with encephalitis and not attributable to another cause *Adapted from reference 1; Confirmed encephalitis requires: pathological confirmation of brain inflammation consistent with encephalitis; pathological, microbiological or serological evidence of acute infection with a microorganism that is strongly associated with encephalitis from an appropriate clinical specimen; or laboratory evidence of an autoimmune condition that is strongly associated with encephalitis