Ischemic colitis (IC)is one of the major causes of acute lower gastrointestinal bleeding and usually occurs in the elderly. Hypoperfusion of the mesenteric microvasculature,even induced by constipation in the elderly,is by far the approximate mechanism. The clinical manifestations of IC vary depending on the extent and duration of ischemia. The presenting symptoms include sudden cramping abdominal pain;an urgent desire to defecate;and passage within 24 hours of bright red or maroon blood or bloody diarrhea. CT scan should be the first imaging modality of choice for patients with suspected IC to assess the distribution and phase of colitis. Early colonoscopy (within 48 hours of presentation)should be performed to confirm the diagnosis if without gangrene and perforation. Nonsurgical treatment approach usually includes bowel rest,intravenous fluid,electrolyte repletion,correction of precipitating conditions and antibiotic usage,occasionally with administration of total parenteral nutrition. It has been shown that isolated right colonic ischemia (IRCI)has a worse outcome than ischemia affecting other regions of the colon. Surgical intervention should be considered in the presence of IRCI or pan-colonic ischemia and in the presence of gangrene.%缺血性结肠炎(IC)多见于老年人群,是急性下消化道出血的主要原因之一.各种原因甚至老年人便秘所致的低血流灌注状态为其主要发病机制.临床表现与缺血累及范围和时间有关.发作性腹部疼痛不适伴排便急迫感、24 h内出现鲜红色或暗红色血便或血性腹泻,是老年人IC的主要临床表现.腹盆腔CT检查是明确肠道受累部位和病变范围首选的检查方法.结肠镜检查为确诊方法,如无肠坏死或肠穿孔,应于48 h内行结肠镜检查.内科治疗包括肠道休息、静脉补液、纠正电解质紊乱、治疗原发疾病和应用抗菌药物,必要时予肠外营养.与其他部位的结肠缺血相比,孤立性右半结肠缺血预后较差.对于孤立性右半结肠或全结肠缺血以及存在肠坏死的患者,应及时请外科会诊讨论有无手术治疗的可能性.
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