11.虚血性腸炎小腸・大腸

Ischemic Colitis and Enteritis

要旨　虚血性大腸炎は，出血を来す代表的な下部消化管疾患である．重症例では壊疽型や狭窄型へ進展する場合があり，病型診断が治療法の選択に重要である．壊疽型や狭窄型への進展例では，大腸内視鏡で評価した病変部粘膜が暗赤色調を呈し浮腫も高度で，特に壊疽型では灰緑色調を呈する．合併する潰瘍も深く，腸管全周に及ぶ場合が多い．治療は，一過性型は保存的治療で良いが，壊疽型は緊急手術が必要である．なお狭窄型では，発病後1か月以上経過しても全周性狭窄部に開放性潰瘍が残存する例では外科手術を考慮する．虚血性小腸炎はまれな疾患で下血を来す頻度は低いが，全周性の管状狭窄へ進展し，外科手術が必要になる場合が多い．

　Ischemic colitis is a representative intestinal disease which causes anal bleeding. In severe cases, sometimes progressing to gangrenous or stricturing type, early estimation of clinical severity is necessary for selecting appropriate treatments. In cases that have progressed to gangrene or the stricturing type, the colonoscopic picture often demonstrates marked congestion and edema with necrosis of colonic mucosa in the early phase of the disease. Longitudinal and irregular-shaped deep ulcers with clear margin are also seen in the lesion. The most characteristic colonoscopic findings of gangrenous type are multiple dome-like mucosal elevations with grayish-green color. As for the treatment, a transient type can be treated conservatively, but a gangrenous type requires an emergency operation. In addition, with the stricturing type, there are times when the intestinal stenosis improves during the course of the disease. Therefore, the indication for surgical operation should be judged by radiographic and colonoscopic findings examined over one month after onset.

　Ischemic enteritis is rare and only occasionally dose it cause anal bleeding. Most of the lesions associated with ischemic enteritis progress to tubular stenosis with a circumferential ulcer, and require surgical intervention.