Anti-NMDAR encephalitis

Anti-NMDA receptor encephalitis (anti-NMDAR encephalitis) is a rare autoimmune encephalitis in which antibodies target N-methyl-D-aspartate (NMDA) receptors on the surface of nerve cells in the brain. These receptors play a critical role in learning, memory, behavior, and communication between neurons. When antibodies disrupt their normal function, they can cause a rapidly developing combination of psychiatric, neurological, cognitive, and autonomic symptoms.

Symptoms often begin with headache, fever, or other flu-like symptoms before progressing over days to weeks. People may develop memory loss, confusion, personality or behavioral changes, anxiety, hallucinations, delusions, speech difficulties, seizures, abnormal involuntary movements, decreased consciousness, sleep disturbances, autonomic dysfunction affecting heart rate, blood pressure, or breathing, and, in severe cases, respiratory failure requiring intensive care.

Some individuals with anti-NMDAR encephalitis also have other autoimmune diseases, including Hashimoto’s thyroiditis, systemic lupus erythematosus, Sjögren disease, or rheumatoid arthritis, although these associations are relatively uncommon. The condition may also overlap with other autoimmune neurological disorders, including myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and, less commonly, neuromyelitis optica spectrum disorder (NMOSD). Ovarian teratomas are the tumor most frequently associated with anti-NMDAR encephalitis, particularly in young adult women.

Anti-NMDAR encephalitis is one of the most common forms of autoimmune encephalitis, although it remains a rare disease overall. It affects females more often than males, particularly during adolescence and early adulthood, but it can occur in both sexes and at any age, including infancy and older adulthood. The disease is associated with ovarian teratomas in a substantial proportion of adult women, while tumors are much less common in children and males. Previous herpes simplex virus encephalitis is also a recognized trigger for some cases. Many people, however, have no identifiable tumor or preceding infection.