- Acute mesenteric ischemia results from arterial (or rarely venous) compromise to the superior mesenteric circulation.
- Emboli and thrombus formation are the most common causes of acute mesenteric ischemia, although nonocclusive mesenteric ischemia from vasoconstriction can also give rise to the disorder.
- Ischemic colitis results from mucosal ischemia in the inferior mesenteric circulation during a low-flow state (hypotension, arrhythmias, sepsis, aortic vascular surgery) in patients with atherosclerotic disease.
- Vasculitis, sickle cell disease, vasospasm, and marathon running can also predispose to ischemic colitis.
- Patients with acute mesenteric ischemia may present with abdominal pain, but physical examination and imaging studies can be unremarkable until infarction has occurred. As a result, diagnosis is late and mortality is high.
- Ischemic colitis may manifest as transient bleeding or diarrhea; severe insults can lead to stricture formation, gangrene, and perforation.
- Urgent angiography is indicated if the suspicion for acute mesenteric ischemia is high.
- In patients with ischemic colitis, characteristic â??thumbprintingâ? of the involved colon may be seen on plain radiographs of the abdomen.
- Colonoscopy may reveal mucosal erythema, edema, and ulceration, sometimes in a linear configuration; evidence of gangrene or necrosis is an indication for surgical intervention.
- Treatment of acute mesenteric ischemia is essentially surgical.
- In patients with ischemic colitis, in the absence of peritoneal signs or evidence of gangrene or perforation, expectant management with fluid and electrolyte repletion, broad-spectrum antimicrobials, and maintenance of an adequate BP usually suffices.
- Evidence of gangrene or necrosis in the setting of ischemic colitis is an indication for surgery.