薬剤性食道炎の内視鏡画像診断

Endoscopic Diagnosis of Drug-induced Esophagitis

要旨●薬剤性食道炎は薬剤投与に関連して発症する食道粘膜障害であり，それぞれの薬剤によりその機序は多様である．ダビガトラン起因性食道炎は，製剤が食道内に停滞することで，コーティングされた酒石酸による局所的な食道粘膜障害を来す．凝固壊死した扁平上皮が，白色膜様物として食道長軸方向に付着する所見は，特徴的な内視鏡所見と考えられた．一方，免疫チェックポイント阻害薬（ICI）による免疫関連有害事象（irAE）に関連した食道炎は，いずれの部位にも生じ得て，内視鏡所見も多彩で非特異的である．診断にはICIの種類や投与期間，併用療法を含む臨床経過の把握および他疾患の除外が重要であり，これにより早期診断・治療につながると考えられた．

　Drug-induced esophagitis is defined as esophageal mucosal injury associated with medication use and may arise through diverse underlying mechanisms. Dabigatran-induced esophagitis occurs when the capsule is retained in the esophagus, where its tartaric acid coating causes localized mucosal injury. The adhesion of the coagulative necrotic squamous epithelium, which appears endoscopically as a longitudinally distributed whitish membranous material, is considered a characteristic finding.

　By contrast, esophagitis associated with immune-related adverse events induced by immune checkpoint inhibitors（ICIs）can occur anywhere in the esophagus and presents with diverse and nonspecific endoscopic findings. Accurate diagnosis requires careful assessment of the clinical course, including ICI type, duration of therapy, and concomitant treatments, together with systematic exclusion of other diseases, to facilitate early diagnosis and appropriate management.