Necrosis may occur but is usually limited to the mucosa and submucosa, only occasionally causing full-thickness necrosis necessitating surgery. Ischemic colitis occurs mainly in older people (> 60) and is thought to be caused by small-vessel atherosclerosis. It can also be a complication of abdominal aortic aneurysm repair.
Symptoms of ischemic colitis are milder and of slower onset than those of acute mesenteric ischemia and consist of left lower quadrant pain followed by rectal bleeding.
Treatment of ischemic colitis is supportive with IV fluids, bowel rest, and antibiotics.
The underlying cause of the low-flow state (eg, control of cardiac arrhythmia) is treated if relevant.
Surgery is rarely required, unless ischemic colitis is a complication of a vascular procedure or there is full-thickness necrosis. About 5% of patients have a recurrence. Occasionally, strictures develop at the site of the ischemia several weeks later, necessitating surgical resection.