Mind in Crisis, Ovary in Question: A Case of Anti-N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis Associated With Ovarian Teratoma.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare but serious autoimmune disorder. It is often associated with ovarian teratomas and mimics psychiatric or infectious conditions, leading to frequent misdiagnosis. Early recognition and treatment are crucial for better outcomes. We present the case of a 31-year-old woman who developed sudden behavioural changes, seizures, and cognitive decline. Initial tests showed no clear cause. The cerebrospinal fluid analysis confirmed anti-NMDA receptor antibodies, and imaging revealed an ovarian teratoma. Immunotherapy alone failed, and tumour removal was necessary for recovery. Her condition improved significantly after surgery. Our case highlights the difficulty of diagnosing autoimmune encephalitis in young women with unexplained neuropsychiatric symptoms. Recognising paraneoplastic causes and using a multidisciplinary approach are essential for timely intervention. Immunotherapy can help, but it may not be enough without tumour removal. Autoimmune encephalitis requires prompt diagnosis and aggressive treatment. Failure to identify and treat underlying causes can lead to severe complications or delayed recovery. This case emphasises the importance of considering anti-NMDA receptor encephalitis in young women with new-onset neuropsychiatric symptoms. Early cerebrospinal fluid analysis and imaging can confirm the diagnosis and guide treatment decisions.