Abstract:Autoimmune encephalitis is rare and has various clinical manifestations, which may hamper the correct diagnosis. Therefore, the pediatrician should be familiar with the clinical symptoms, signs, laboratory features, neuroimaging changes, immunological characteristics, and differential diagnosis of this disease. In order to correctly diagnose anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, cerebrospinal fluid (CSF) examinations including detection of oligoclonal bands, brain MRI scanning, and routine EEG and/or 24 hours video EEG should be performed in children. For highly suspected cases, particularly children presenting with psychiatric symptoms and epileptic seizures, examinations should be done to detect anti-NMDAR antibodies (Abs) in serum and CSF. A notable feature in children is the EEG pattern named "extreme delta brush", which may help confirm the clinical diagnosis. Anti-NMDAR Abs in CSF is the diagnostic "gold-standard" for this disease. The differential diagnosis of anti-NMDAR encephalitis is broad. In pediatric patients, the differential diagnosis should be made mainly with herpes simplex virus encephalitis, other autoimmune encephalitis, and psychosis.