Anti-Nmda Receptor Encephalitis

Key points

• Anti-NMDA receptor encephalitis is an autoimmune encephalitis presenting with prominent PSYCHIATRIC features — agitation, psychosis, hallucinations — often mistaken initially for a primary psychiatric illness.
• It then progresses to seizures, a movement disorder (orofacial dyskinesias), reduced consciousness and autonomic instability.
• It may be paraneoplastic — classically associated with OVARIAN TERATOMA in young women, so imaging to look for an underlying tumour is part of the work-up — but many cases have no identified tumour, so it is not always paraneoplastic.
• Diagnosis rests on anti-NMDA receptor antibodies (CSF testing is more sensitive than serum); management is immunotherapy plus removal of any tumour found.