A patient with a long history of relapsing psychosis and mania presenting with anti-NMDA receptor encephalitis ten years after first episode

Anti-N-methyl- D-aspartate receptor (NMDAR) encephalitis is a recently discovered autoimmune disorder, in which antibodies target NMDARs in the brain, leading to their removal from synapses. Early in the disease course, patients often present with marked psychosis and mood disturbances (i.e. mania, depression), explaining why most of these patients are first seen by psychiatrists. Hence, autoimmune encephalitis is receiving growing attention from psychiatry, mainly owing to concerns over misdiagnosing immunomediated and potentially curable disorders as primary psychiatric disorders, such as schizophrenia or major depressive disorder. Although anti-NMDAR encephalitis occurs in the context of new-onset psychiatric symptoms, there is a lack of information on differential diagnosis and treatment of this disorder after a long-term diagnostic history of functional psychiatric disorders. We report a case of a patient with a long history of bipolar affective disorder evolving with anti-NMDAR encephalitis, initially misdiagnosed as non-organic psychosis.

抗N-甲基-D-天冬氨酸受体（NMDAR）脑炎是一种新近发现的自身免疫性疾病，患者体内的抗体靶向大脑中的NMDAR，导致受体从突触处被清除。在疾病病程早期，患者常表现出显著的精神病性症状与心境障碍（如躁狂、抑郁），这也是此类患者最初多由精神科医师接诊的原因。因此，自身免疫性脑炎正受到精神医学界越来越多的关注，这主要源于学界对将免疫介导且具有潜在治愈可能的疾病误诊为精神分裂症、重度抑郁障碍等原发性精神疾病的担忧。尽管抗NMDAR脑炎常以新发精神症状起病，但对于既往存在长期功能性精神疾病诊疗史的患者，目前仍缺乏关于该疾病鉴别诊断与治疗的相关信息。本文报告一例长期罹患双相情感障碍的患者并发抗NMDAR脑炎的病例，该患者最初被误诊为非器质性精神病。