—薬剤関連消化管病変の臨床的特徴—青黛による虚血性腸病変

Indigo Naturalis-associated Ischemic Intestinal Lesions

要旨●筆者らは，植物から抽出された生薬である青黛の潰瘍性大腸炎患者における粘膜治癒促進の有効性を報告してきた．一方で，自己購入した青黛の服用による肺動脈性肺高血圧症や腸重積といった有害事象の存在が明らかとなってきた．青黛による腸重積や非特異性腸炎などの腸病変は右側結腸に好発する．多彩な内視鏡像を示すが，孤発性の潰瘍形成や虚血性腸炎様の発赤・浮腫状粘膜などが特徴である．発症のメカニズムはまだ明らかでないが，病理組織学的に小血管における静脈炎の存在が示されており，吸収された青黛代謝産物が虚血性病変を来す一因となった可能性が示唆される．何よりもまず，青黛について知り，その有害事象の可能性を疑うことが重要である．

　Recently, we reported the efficacy of a herbal medicine indigo naturalis in terms of inducing mucosal healing in patients with UC（ulcerative colitis）. Meanwhile, adverse events, including pulmonary arterial hypertension and intussusception, were identified among patients with UC who used self-purchased indigo naturalis. Indigo naturalis-associated intestinal lesions, such as intussusception and nonspecific colitis, were more frequently diagnosed in the right side of the colon. Endoscopic findings varied, but were often characterized by solitary ulcer formation and/or an ischemic, colitis-like, reddish edematous mucosa. Although the mechanism of the disease is unclear, histopathological examination revealed the presence of phlebitis in the small blood vessels, suggesting that absorbed metabolites of indigo naturalis contribute to the development of the ischemic lesions. Therefore, awareness of the use of indigo naturalis and associated adverse events is important.