The Facts About Ischemic Colitis

Medically Reviewed by Arefa Cassoobhoy, MD, MPH on September 20, 2023
4 min read

Ischemic colitis is inflammation in your large intestine, or colon. It results from a lack of blood flow to the area, usually because an artery is blocked or narrowed.

You need blood flow to your colon because it brings oxygen that keeps your tissues alive. If the blockage goes on for too long, it can cause serious problems. But if you get treatment soon, you should heal quickly. Ischemic colitis is more common in people over 60, but younger folks can get it, too. You may hear your doctor call it ischemic bowel disease.

You may notice:

Doctors often can’t pinpoint the cause of ischemic colitis. But these things can raise your odds of getting it:

  • Chronic constipation. This raises pressure inside your colon and makes it hard for blood to flow. If you have irritable bowel syndrome with constipation, you may be at even more risk.
  • Hardening of the arteries (atherosclerosis). Fatty gunk can build up and clog the arteries in your intestines.
  • Very low blood pressure or flow. This causes colon arteries to tighten and send more blood to your brain. A number of health problems can cause low blood pressure. But dehydration, heart failure, large blood loss, and shock are the leading reasons.
  • A blood clot. One can form inside an artery wall or break off from somewhere else and move toward your colon. Certain health problems you get from your parents at birth can cause blood to clot too easily. Your doctor may give you tests to see if you have one of these conditions.
  • Bowel blockage. This can result from a hernia, scar tissue, or a tumor.

Surgery to repair an aortic aneurysm (a bulge in the artery) can lead to ischemic colitis. Other operations in your belly or your circulatory system can also cause problems.

The risk also goes up if you’re a long distance runner. During a marathon, blood flow may shift away from your gut to meet the oxygen needs of your leg muscles. Dehydration could play a role, too.

It’s rare, but some medications can trigger an ischemic colitis attack. These include:

Ischemic colitis is a master of disguise. Its symptoms can mimic other conditions, including a flare of ulcerative colitis or Crohn’s disease. Those long-lasting conditions result from a problem with your immune system, not low blood flow.

Doctors may ask for any of these tests to decide if you have ischemic colitis:

  • Imaging tests, like CT scans and angiograms. These use X-rays at different angles to get a detailed image of your colon and blood vessels.
  • Stool samples. Doctors look for infections that may be causing your symptoms.
  • Colonoscopy. This test looks inside your colon. The doctor also may take tissue samples to confirm a diagnosis.

If you have a mild case -- and most cases are mild -- the inner lining of your colon is inflamed, sore, and bleeding. It usually heals on its own, but you may get antibiotics to prevent infection.

You’ll probably get IV fluids to keep you hydrated. To give your colon a rest while it heals, you won’t be able to drink or eat anything for a few days.

If you have a more serious case, a surgeon may need to remove dead tissue or repair your bowel.

After your treatment, you may need another colonoscopy to make sure there are no lasting problems.

For most people, an ischemic colitis attack is a one-time thing -- it never happens again. In others, it can become an ongoing problem.

You might be able to prevent another episode. To stack the odds in your favor:

  • Stay hydrated.
  • Discuss your medications with your doctor. If one med triggered the problem, the doctor may know of others that will work better for you.
  • Stop smoking. It damages virtually all your organs, including blood vessels.

This condition results from a blocked artery. If you have it, you should eat a low-fat diet similar to what people with heart disease eat. Multiple small meals may be a better option, too. You may notice pain after you eat a fatty meal.

If you have ischemic colitis and have pain on your right side or sudden belly pain that’s so severe you can’t find a comfortable position, head to the ER or call 911.

The artery feeding the right side of your colon also feeds part of the small intestine. A blockage there can quickly damage or kill tissue. If this life-threatening situation occurs, you'll need surgery to clear the blockage and to remove the damaged part of the intestine.