無症候性ダビガトラン起因性食道粘膜障害の1例

Dabigatran-induced Asymptomatic Esophageal Mucosal Injury, Report of a Case

要旨●70歳代，男性．心房細動に対してダビガトランが処方された．3日後の内視鏡検査で上部食道に白色調の不整な粘膜肥厚を柵状に認めた．10日後には病変は上・中部食道に全周性に拡がり，生検で食道扁平上皮の凝固壊死を認めた．ダビガトランをワルファリンに変更したところ，4週後に病変は消失しており，ダビガトラン起因性食道炎と診断した．患者は経過を通して無症状であった．ダビガトランは直接トロンビン阻害作用を持つ新規経口抗凝固薬である．近年，ダビガトラン服用後の胸痛・胸焼けを伴う食道粘膜障害が報告されているが，本例は無症状で内視鏡像も既報と異なっていた．ダビガトラン服用者の一部は無症候性の食道粘膜障害を有している可能性が示唆された．

　A 75-year-old Japanese male was prescribed dabigatran capsules for atrial fibrillation. Three days after administration, endoscopy revealed a whitish and irregularly-surfaced mucosal thickening longitudinally situated in the upper esophagus. Ten days after dabigatran administration, the lesion had circumferentially spread over the upper and middle esophagus, and biopsy revealed an esophageal mucosal coagulation necrosis. Dabigatran capsules were considered a possible cause, and treatment was changed to warfarin. Four weeks later, the lesion completely disappeared. The patient experienced no subjective symptoms throughout the clinical course.

　Dabigatran, a novel oral anticoagulant, directly inhibits thrombin. Recently, several studies have reported dabigatran-induced esophageal mucosal injury with chest pain or heart burn. This case showed a remarkably different endoscopic finding from previous reports and no subjective symptoms, suggesting that other individuals treated with dabigatran capsules may have asymptomatic esophageal mucosal injury.