メサラジン製剤による小腸炎の1例

Enteritis Caused by Mesalazine, Report of a Case

要旨●70歳代，女性．1年前，近医で全大腸型の潰瘍性大腸炎（UC）と診断され，メサラジン製剤とプレドニゾロンで加療を開始された．経過中に下痢の増悪と腹痛を認め，UC増悪と診断された．顆粒球吸着療法にて血中CRPの低下と腹痛の改善は認めたが，下痢症状が改善せず当院に転院となった．大腸内視鏡検査，血液検査ではUC増悪は否定的で，ダブルバルーン小腸内視鏡検査にて回腸に白苔付着の強い全周性の浅い潰瘍と粗糙な粘膜を認めた．薬剤性小腸炎の可能性を疑い，メサラジン製剤の内服を中止したところ，症状は速やかに改善した．内服中止の約2週間後には小腸粘膜の改善を認め，DLSTでもメサラジン製剤が陽性を示し，メサラジン起因性小腸炎と診断した．

　A 72-year-old woman was diagnosed with UC（ulcerative colitis）1 year ago. Although she had been treated with prednisolone and mesalazine, her diarrhea had exacerbated and abdominal pain was also observed. The referring doctor started granulocytapheresis, and both CRP and abdominal symptoms improved. However, her diarrhea failed to improve ; therefore, she was referred to our hospital. Colonoscopy and blood test indicated that the possibility of UC exacerbation was low. Antegrade double-balloon endoscopy revealed a circular shallow ulcer in the ileum with strong mucus adhesion and a rough mucous membrane. We suspected drug-induced enteritis, and discontinued mesalazine therapy, after which her symptoms diminished promptly. We confirmed mucosal improvement in the ileum by double-balloon endoscopy 2 weeks after mesalazine cessation. In addition, mesalazine showed a strong reaction in a drug-induced lymphocyte stimulation test. Finally, she was diagnosed with mesalazine-induced enteritis.