impairment of the blood flow to the arteries that supply the small and large intestine. The arteries include the *coeliac axis and the superior and inferior mesenteric arteries. Partial or total occlusion of blood flow may occur abruptly or over a protracted period (acute vs. chronic mesenteric ischaemia). Causes of an acute episode include migration of an arterial blood clot or embolus into the mesenteric vessels, an arterial blood clot in patients with atherosclerosis, profound low blood pressure, or states promoting coagulation. Typically a patient presents with severe abdominal pain, nausea and vomiting, diarrhoea, and rectal bleeding. Rapid diagnosis is essential since impaired intestinal blood flow predisposes to the development of gangrene and necrosis of the bowel. Treatment includes aggressive fluid resuscitation, pain relief, antibiotics, surgical resection of nonviable bowel, and radiological or surgical *revascularization of implicated arteries. In chronic mesenteric ischaemia, abdominal pain precipitated by eating is the main symptom, often accompanied by loss of appetite and marked weight loss.
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