Algorithm for the diagnosis and management of colonic ischemia

SBP: systolic blood pressure; HR: heart rate; WBC: white blood cell count; Hgb: hemoglobin; BUN: blood urea nitrogen; LDH: lactate dehydrogenase; CT: computed tomography; IV: intravenous.
* Abdominal pain, cramping, urgent desire to defecate, lower gastrointestinal bleeding, diarrhea.
¶ Severe colonic ischemia includes any of the following: peritoneal signs on physical examination; pneumoperitoneum, pneumatosis, or portal venous gas on radiologic imaging; gangrene on colonoscopic examination; pancolonic ischemia or colon involvement isolated to the right side on imaging by colonoscopy or CT; or more than three of the risk factors commonly associated with a poorer outcome (refer to central box of algorithm).
Δ CT with IV (and oral contrast, if tolerated) is the initial imaging study. Multiphase CT angiography is indicated for patients with suspected vascular occlusion (eg, colonic involvement isolated to the right indicating possible superior mesenteric artery occlusion). Bowel findings include mural thickening, edema, and thumbprinting.
◊ Examples include intestinal obstruction or inflammatory bowel disease.
§ Mild disease includes that with typical symptoms of colon ischemia but none of the risk factors commonly associated with a poorer outcome (refer to central box of algorithm).
¥ Moderate colonic ischemia includes those with typical symptoms and one to three risk factors commonly associated with a poorer outcome (refer to central box of algorithm).
‡ Colonoscopy should be performed in suspected cases to confirm the diagnosis. The colon should be insufflated minimally. For moderate-to-severe disease, limited sigmoidoscopy or colonoscopy is appropriate to confirm disease prior to exploration, stopping at the distal-most extent of the disease. Biopsies of the colonic mucosa should be obtained except in cases of gangrene.
† Conventional catheter-based arteriography may be indicated if vascular occlusion is demonstrated or strongly suspected, such as with colonic involvement isolated to the right side.
** The approach to revascularization, if indicated, may be endovascular or open depending upon the nature of the lesion.