薬剤性開咬の症例シリーズ：向精神薬に関連した錐体外路症状

Case series of drug-induced open bite: Extrapyramidal symptoms related to psychotropic medications.

抄録

はじめに:

薬剤性開咬は、筋緊張の異常を伴う錐体外路症状のひとつであり、歯科領域で認められることは稀である。本症例は、薬剤性開咬患者の詳細な愁訴を含む臨床的特徴を検討するための後方視的症例研究である。

INTRODUCTION: Drug-induced open bite is one of the extrapyramidal symptoms with abnormal tonus of muscles and is rarely recognized in dentistry. This is a retrospective case study to investigate clinical characteristics including detailed complaints in patients with drug-induced open bite.

方法:

2013年9月から2022年9月までに東京医科歯科大学病院歯科心療内科を初診した外来患者のうち、薬物性開咬と診断された患者を対象とした。性別、年齢、詳細な愁訴、罹病期間、異常所見、初診時に内服していた向精神薬などの薬剤、精神疾患の併存状況、罹病期間、その他の病歴などの臨床的特徴を、カルテを確認することで後方視的に収集した。

METHODS: Of the outpatients who first visited the psychosomatic dental clinic at the Tokyo Medical and Dental University Hospital between September 2013 and September 2022, the patients diagnosed with drug-induced open bite were involved in this study. The clinical characteristics including sex, age, detailed complaints, duration of illness, abnormal findings, psychotropic medications, and other medications that were taken at the first examination, psychiatric comorbidities, the duration of psychiatric diseases, and other medical histories were collected retrospectively by reviewing their medical chart.

結果:

薬剤性開咬は11例に認められた［女性：7例、男性：4例、年齢中央値：49歳（36.5歳、53歳）］。食事困難、特に咀嚼困難が主訴であり（9/11、81.6％）、罹病期間は48.0（16.5、66）ヵ月であった。開咬の程度は様々であった。前歯の咬合接触がない症例もあれば、第2大臼歯にのみ咬合接触がある症例もあった。3症例は予後の経過観察が可能であったが、1症例は6ヵ月の経過観察で薬剤性開咬が改善したが、2症例は改善せず、1症例は臼歯の突出がみられた。全例に精神疾患が併存しており、最も多い診断名は統合失調症（＝5例）、うつ病（＝5例）、次いで不眠症（＝1例）、自閉症スペクトラム障害（＝1例）であった（重複診断を含む）。9例（81.6％）が抗精神病薬による治療を受けており、うち3例は抗うつ薬も服用していた。

RESULTS: Drug-induced open bite was found in 11 patients [women: 7, men: 4, median of age: 49 (36.5, 53) years old]. Difficulty in eating especially chewing was the major complaint (9/11, 81.6%) with the duration of illness as 48.0 (16.5, 66) months. Various degrees of open bite were observed. While some showed no occlusal contact on frontal teeth, some showed occlusal contact only on the second molars; moreover, the jaw showed a horizontal slide in a few patients. Three cases could be followed up for prognosis; while in one case the drug-induced open bite improved with 6 months of follow-up, two cases did not improve, and one showed extrusion of molars. All of them had psychiatric comorbidities with the most common diagnosis being schizophrenia ( = 5) and depression ( = 5) followed by insomnia ( = 1) and autism spectrum disorder ( = 1) including duplicated diagnosis. Nine patients (81.6%) had been undergoing treatment with antipsychotics of which three patients were also taking antidepressants.

考察:

薬剤性開咬はまれな症状であるが、歯科医と精神科医が連携して的確な診断と適切な管理を行うためには、口腔内の評価に加え、症状、精神疾患の併存、向精神薬の服用歴などについての慎重な問診が必要である。

DISCUSSION: Although a drug-induced open bite is a rare symptom, prudent medical interviews about symptoms, psychiatric comorbidities, and psychotropic medication history besides oral assessment are necessary to provide a precise diagnosis and appropriate management in collaboration between dentists and psychiatrists.