Ischemic colitis is injury of the large intestine that results from an interruption of its blood supply.

• Abdominal pain and bloody stools are common.
• Computed tomography is usually done, and colonoscopy is sometimes done.
• Most people get better with fluids given by vein and by not eating anything, but a few require surgery.

Ischemic colitis results from a temporary blockage of blood flow through arteries that supply the large intestine. Often doctors cannot find a cause for the reduced blood flow, but it is more common among people with heart and blood vessel disease, people who have had surgery on their aorta, or people who have problems with increased blood clotting. Ischemic colitis affects primarily people who are 60 or older.

Blockage of blood flow damages the inside lining and inner layers of the wall of the large intestine, causing ulcers (sores) in the lining of the large intestine, which can bleed.

Symptoms and Diagnosis

Usually, the person experiences abdominal pain. The pain is felt more often on the left side, but it can occur anywhere in the abdomen. The person frequently passes loose stools that are often accompanied by dark red clots. Sometimes bright red blood is passed without stool. Low-grade fevers (usually below 100° F [37.7° C]) are common.

A doctor may suspect ischemic colitis on the basis of the symptoms of pain and bleeding, especially in a person older than 60. It is important for doctors to distinguish ischemic colitis from acute mesenteric ischemia, a more dangerous condition in which blood flow to part of the intestine is completely and irreversibly blocked (see Gastrointestinal Emergencies: Acute Mesenteric Ischemia). Doctors usually do computed tomography and sometimes also colonoscopy (examination of the large intestine with a flexible viewing tube) to distinguish ischemic colitis from other forms of inflammation, such as infection or inflammatory bowel disease.

Prognosis and Treatment

People with ischemic colitis are hospitalized. Initially, the person is given neither fluids nor food by mouth so that the intestine can rest. Instead, fluids, electrolytes, and nutrients are given by vein (intravenously). Antibiotics are often given to prevent infection that might follow the inflammation. Within a few days, antibiotics are usually stopped and eating is resumed. Nearly all people with ischemic colitis improve and recover over a period of 1 to 2 weeks. However, when the interruption to the blood supply is more severe or more prolonged, the affected portion of the large intestine may have to be surgically removed. Rarely, people get better but later on develop a scar in the affected area, causing a partial obstruction requiring surgical repair.

Last full review/revision October 2012 by Parswa Ansari, MD