Ischemic Colitis

Front view of colon showing arteries supplying blood to colon.

Ischemic colitis happens when blood flow to the colon is reduced or blocked. Bloody diarrhea and severe belly pain are the most common symptoms. Other symptoms include vomiting, fever, and fainting. Diarrhea can lead to severe dehydration. This is the rapid loss of the fluids your body needs to function. Because of the severe pain and the risk for dehydration, ischemic colitis should be treated right away.

Causes of ischemic colitis

The cause of the reduction or blockage of blood flow to the colon is not well understood. In some cases, a sudden drop in blood pressure, or dehydration, leads to an episode. Ischemic colitis is more likely in people with blood clotting problems or heart and blood vessel disease.

Diagnosing ischemic colitis

The presence of severe belly pain and bloody diarrhea is often enough to diagnose ischemic colitis. After these symptoms are treated, a test called a colonoscopy will likely be done. This helps rule out other colon problems. The test uses a thin, flexible scope with a light and camera on the end. The scope is inserted through the rectum into the colon. The scope sends pictures from inside the colon to a video screen. A small sample of tissue (biopsy) from the colon may be taken for further testing in a lab.

Treating ischemic colitis

Episodes are treated in the hospital. You may remain in the hospital for several days or longer:

  • An IV line is put into a vein in your hand or arm. You will be given fluids through the IV to treat dehydration. You are also given IV pain medicines if you need them.

  • You may be given IV antibiotics (medicines that treat infection).

  • To rest the bowel, you will not eat or drink for a few days. In rare cases, when symptoms are very severe, you will be given nutrition through the IV.

  • If you lost a lot of blood during the episode, you may receive a blood transfusion.

  • In rare cases, an episode causes severe damage to the colon. In this case, surgery may need to be done to remove the damaged section. Your healthcare provider can tell you more if this is needed.


While you are being treated, your healthcare provider will work to find the cause of your ischemic colitis. After you recover, you may need to make lifestyle changes, such as quitting smoking, or take medicines to decrease your risk of another episode. Call 911 or go to the emergency room right away if your symptoms return.