Anti-N-methyl-D encephalitis.

Anti-N-methyl-D-aspartate receptor encephalitis is a rare and serious autoimmune disorder, usually part of a paraneoplastic syndrome. Patients present with a change in mental status, bizarre behavior, and seizures. There are many neoplastic and infectious etiologies, with 90 percent of documented cases in young women, frequently with an ovarian teratoma. Damage to limbic brain receptors is most often induced by teratoma cell-produced anti-N-methyl-D-aspartate antibodies. Treatment targets the specific oncologic or infectious cause and/or employs steroids, plasmapheresis, or other anti-inflammatory therapies. Neurological sequellae persist 75 percent of the time, relapse occurs in 20 percent of cases, and the mortality rate is 25 percent.