ISCHEMIC PROCTOSIGMOIDITIS

Rectal ischemia is rare because of excellent collateral supply, Althou gh rectosigmoid ischemia is usually accompanied by more proximal colon ic involvement, it may occur alone. Methods: A retrospective review of all patients diagnosed as having colonic ischemia at the Mayo Clinic from 1976 to 1991 was performed. Clinical, endoscopic, radiological, a nd pathological data were obtained from patient charts. Patients with involvement of the rectosigmoid colon extending to no more than 30 cm above the dentate line on endoscopy were included in the study. A sing le radiologist reviewed CT scans and aortograms, and a single patholog ist reviewed tissue specimens. Results: Ten of 328 patients with ische mic colitis had isolated ischemic proctosigmoiditis. Six patients had acute ischemia (i.e., symptom duration of less than 4 wk), and four ha d chronic ischemia (symptoms for 4 wk or longer). Ischemic proctosigmo iditis affects elderly patients with atherosclerosis. An identifiable precipitating factor, such as a major illness or hemodynamic disturban ce, was identified in four of six patients with acute ischemic proctos igmoiditis and in one of four patients with chronic ischemic proctosig moiditis. CT revealed rectal wall thickening and/or perirectal strandi ng. Angiography may demonstrate atheromatous disease of the aortoiliac vessels, Acute and ''chronic'' presentations had similar histopatholo gical changes. Conclusions: Ischemic proctosigmoiditis is rare, In con trast to generalized colonic ischemia, patients with acute rectal isch emia often have clearly identifiable precipitating factors. Conservati ve management is appropriate for uncomplicated acute ischemic proctosi gmoiditis. Patients with chronic ischemic proctosigmoiditis may develo p bowel perforation necessitating a proctectomy or colonic diversion. Recognition of this entity and differentiation from idiopathic inflamm atory bowel disease is important to determine appropriate therapy.