富山県内の精神科医における抗NMDA受容体脳炎の認知度調査

A Survey of Psychiatrists to Determine Their Level of Familiarity with Anti-N-methyl-D-aspartate Receptor Encephalitis

はじめに

　抗NMDAR（N-methyl-D-aspartate receptor）脳炎は2007年にDalmauら¹⁾によって提唱された疾患であり，抗NMDAR抗体を介して発症する自己免疫性脳炎の1つである。Dalmauらの施設では2007年以降，3年間で400例の臨床データが集積され，稀ではない疾患と考えられる²⁾。また，わが国においても各施設から症例が報告され，2012年2月の時点における医中誌Webでの検索では72例の報告があり，発症率は不明であるが，稀ではない疾患と考えられる。

　抗NMDAR脳炎は精神症状で発症することが多いため，臨床の現場では最初に精神科で診療され，神経内科に紹介されて受診するまでに時間を費やすことがある^3,4)。一方，抗NMDAR脳炎では，早期に診断し速やかに腫瘍切除や免疫療法を行うことが，機能予後の改善につながると報告されている^2,3,5,6)。したがって，抗NMDAR脳炎の患者を最初に診療する可能性が高い精神科医が，急性に精神症状を生じる疾患の鑑別疾患の1つとして抗NMDAR脳炎を認知することが望まれる。

　そこで，精神科医における抗NMDAR脳炎の認知度の現状を確認するため，筆者らは富山県内の精神科医を対象にアンケート調査を行い検討した。

Abstract

　As anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis develops with incipient psychiatric symptoms in most patients, they initially seek medical care at psychiatric services. It would be desirable, therefore, for psychiatrists to be well aware of anti-NMDAR encephalitis. From this point of view, we conducted a questionnaire survey of psychiatrists to explore the present status of their level of awareness about anti-NMDAR encephalitis. A questionnaire survey of 115 psychiatrists engaged in medical care in Toyama Prefecture was conducted to explore their level of familiarity with anti-NMDAR encephalitis. Responses to the questionnaire were received from 76 psychiatrists (response collection rate 66.1%). The mean tenure in the medical profession was 23.5 ± 13.8 years for the 76 psychiatrists, of whom 61 (80.3%) were psychiatric specialists. As for the level of awareness of anti-NMDAR encephalitis, there were 37 doctors (48.7%) who were "not aware of this disorder," 23 (30.3%) who were "aware of only the name of this disorder," and 16 (21.0%) who had "knowledge of an outline of this disorder." While the level of familiarity of doctors with "knowledge of an outline of this disorder" was unrelated to whether the doctor was a specialist, the tenure in the medical profession was significantly shorter for these doctors than for the others (P ＜ 0.05). Of the doctors who were "not aware of this disorder" and those who were "aware of only the name of this disorder," a high percentage comprised physicians working at hospitals/clinics specializing in psychiatry (P ＜ 0.05). Only 7 doctors had encountered case(s) of anti-NMDAR encephalitis (9.2%), and among them, a significantly high percentage was on the staff of polyclinic hospitals (P ＜ 0.05). The present survey revealed low levels of familiarity of psychiatrists with anti-NMDAR encephalitis, and this highlights the importance of further improving the awareness of psychiatrists about the concept of anti-NMDAR encephalitis. (Received: March 28, 2012, Accepted: May 23, 2012)