Anti-NMDA receptor encephalitis with the initial presentation of psychotic mania.

We report a 16-year-old girl with suspected psychotic mania, who subsequently developed amnesia, catatonia, oro-lingual dyskinesia, consciousness disturbance, seizure and respiratory failure. Repeated studies of the cerebrospinal fluid (CSF), viral culture and serology, brain MRI, single photon emission CT scan, and autoimmune profiles were all normal. She was finally diagnosed with anti-N-methyl D-aspartate receptor (NMDAR) encephalitis based on the positive finding of NMDAR antibodies in CSF. Her abdominal CT scan showed no detectable malignancy and pulse steroid therapy failed to have any effect. After administration of intravenous immunoglobulin her consciousness improved gradually. Anti-NMDAR encephalitis, with a characteristic neuropsychiatric syndrome, predominantly affects females with an ovarian tumor and is frequently misdiagnosed as a psychiatric disorder. Immunotherapy and eradication of associated malignancy are the main treatment strategies. Early recognition and early intervention of the disease should improve the outcome.