Intestinal ischemia

A vascular emergency of the gastrointestinal tract usually results from a disturbance in the arterial blood supply or venous drainage of the bowel with consequential severe ischemic injury. Such severe ischemia manifests as gangrene and perforation or less commonly as stricture formation with intestinal obstruction. Vascular emergencies much more commonly involve the small intestine than the colon. Indeed, most cases of colon ischemia resolve spontaneously without sequelae [1-3]. Acute ischemic injury to the small bowel is referred to as "acute mesenteric ischemia" (AMI) and may be arterial or venous; arterial causes of AMI are more common and include superior mesenteric artery embolus (SMAE), superior mesenteric artery thrombosis (SMAT), and nonocclusive mesenteric ischemia (NOMI). Venous forms of AMI tend to result from superior mesenteric venous thrombosis (MVT). Regardless of the cause of the ischemic insult, the end results are similar: a spectrum of bowel injury that can range from mild alteration in bowel function to vascular emergencies with transmural necrosis and intestinal gangrene. Early recognition, appropriate diagnostic studies, and aggressive treatment of the latter are essential if the usually poor outcome is to be improved. This article discusses the presentation, diagnosis, and treatment of these conditions.