Clinical approach to the diagnosis and successful management of anti-NMDA receptor encephalitis when antibody testing is not possible.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a multistage illness that progresses from psychosis, memory deficits, seizures and language disintegration to a state of unresponsiveness with catatonic features often associated with abnormal movements, and autonomic and breathing instability. While the disorder predominantly affects children and young adults, and occurs with or without tumour association, the presence of a tumour (usually an ovarian teratoma) is dependent on the age, sex and ethnicity.Teratomas present more frequently in women older than 18 years, and are more predominant in black women than Caucasians. Here we present the case of a patient with probable anti-NMDA receptor encephalitis. She was subsequently found to have a mature teratoma of the ovary (dermoid cyst). Despite immune-modulated therapy, surgery was eventually performed to remove the cyst. This was met with a good clinical recovery.