Case of autoimmune polyendocrine syndrome type 3 complicated with anti-N-methyl-D-aspartic acid-receptor encephalitis

Anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis is an autoimmune disorder in which autoantibodies in the limbic system bind to GluN1 subunits of NMDA-Rs in the brain. We report a rare case of autoimmune polyendocrine syndrome type 3 complicated by anti-NMDA-R encephalitis. After hospitalization for type 1 diabetes, the 39-year-old patient developed various schizophreniform symptoms and seizures after cold-like symptoms. These findings are consistent with the diagnosis of anti-NMDA-R encephalitis. Immune-related encephalitis was suspected at the early phase of the disease, and cerebrospinal fluid was positive for anti-NMDA-R antibody. Early steroid pulse therapy was initiated during the disease course. The condition improved gradually to full recovery. Early detection and treatment of anti-NMDA-R encephalitis should enhance a positive outcome, considering that besides thyroid diseases and type 1 diabetes, various autoimmune diseases are associated with autoimmune polyendocrine syndrome type 3.