An Overview of Ischemic Colitis

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Ischemic colitis is when the blood flow to the large intestine is interrupted. Constant blood flow to the intestines is needed to keep those organs healthy, and when illness or injury causes blood vessels to be blocked or narrowed, it can cause ischemic colitis. Ischemic colitis can occur at any age but it is more common in people over the age of 60 years. Ischemic colitis is usually treated in the hospital with supportive measures, but in some cases, surgery might be needed. Most of the time, ischemic colitis occurs slowly over time, but in some cases, it can start suddenly (be acute). Acute ischemic colitis is a medical emergency, which is why it is important to see a physician immediately when there is severe abdominal pain.

Ischemic colitis is not related to ulcerative colitis, a form of inflammatory bowel disease (IBD). “Colitis” is a term that refers to inflammation in the colon, which can be caused by a variety of diseases and conditions. Ischemic colitis is, however, associated with heart disease, and maintaining a healthy lifestyle through diet and exercise is important to reducing the risk. In most cases, ischemic colitis is treated successfully and resolves in a few days without complications. Ischemic colitis usually doesn’t occur again and people recover well.

Woman holding abdomen
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There are three main arteries that bring blood to the intestines, called mesenteric arteries. Oxygen-rich blood is needed by all organs in the body in order to function properly, and the mesenteric arteries are the pathway providing that blood to the intestines. If these arteries are partially or totally blocked or narrowed, blood flow is reduced (which is called an infarction), and cell death can start to occur in the large (and sometimes small) intestine. There are a few different reasons why the mesenteric arteries might become blocked:

  • High cholesterol: The mesenteric arteries can become blocked when there is a buildup of plaque inside them. Plaque is made up of cholesterol, fat, cellular waste products, calcium, and fibrin. When plaque is blocking arteries it is a condition called atherosclerosis. In people who have coronary artery disease or peripheral vascular disease, atherosclerosis is a common cause of ischemic colitis.
  • Blood clot: Another cause of ischemic colitis is blood clots. When platelets and plasma proteins in the blood stick together, they can form a clot that's big enough to block all or part of an artery. Blood clots can occur after an injury but they are also a complication of several other diseases and conditions and as an adverse event of some medications.
  • Surgery: Surgery on an artery can cause scar tissue to form. In some cases, scar tissue can occur to such an extent that it blocks the inside of blood vessels.
  • Drug use: Both cocaine and methamphetamine are associated with ischemic colitis. That is because these drugs can cause blood vessels to narrow.

Risk Factors

Some of the risk factors for ischemic colitis include:

  • Age over 60 years
  • Congestive heart failure
  • Diabetes
  • Low blood pressure
  • Medications (although rare), including antibiotics, chemotherapy, hormones (estrogen), IBS-related constipation meds, and pseudoephedrine
  • Previous surgery on the aorta


Typically, the symptom that most people with ischemic colitis have is sudden, cramp-like abdominal pain. This pain might be more noticeable after eating and there might also be tenderness in the belly. In most cases the pain is moderate, but if the blocked arteries are located on the right side of the abdomen, the pain might be severe. These right-sided arteries serve both the large intestine and the small intestine. When there is small intestine involvement with ischemic colitis, the condition may be more painful and also have a greater risk of serious complications.

Ischemic colitis can also cause bloody stools, with the blood being on the spectrum of bright red to maroon. Nausea, diarrhea, vomiting, fever, and an urgent, frequent need to use the toilet are other potential symptoms of ischemic colitis.


A physician may diagnose ischemic colitis based on several factors, including a careful physical history and the results of certain tests. Because ischemic colitis tends to cause some of the same symptoms of IBD (the two main forms being Crohn’s disease and ulcerative colitis), care must be taken to differentiate between these conditions. In some cases, making a diagnosis of ischemic colitis may be challenging because the symptoms are similar to that of other conditions.

Some tests that might be used in the course of making a diagnosis include:

  • Colonoscopy: A colonoscopy is a test where a tube with a light on the end is inserted into the anus to see inside the large intestine.
  • Computed tomography (CT) scan: A CT scan is a type of x-ray that’s used to see the tissues and organs in the abdomen.
  • Mesenteric angiogram: During this test, a contrast dye is injected into one of the mesenteric arteries, via the groin area. X-rays are then taken to see the inside of the artery.
  • White blood cell (WBC) count: A white blood cell count that’s higher than normal means that there is inflammation in the body which could be associated with ischemic colitis.
  • Lactate level: Surgeons use the lactate level along with symptoms to decide on emergency surgery.


Therapy for ischemic colitis will depend on the severity of the condition, with acute disease needing more aggressive treatments. In cases where the condition is considered mild, treatment may consist of a course of antibiotics, a liquid diet, intravenous fluids, and pain management. If the ischemic colitis is found to be resulting from another condition, that underlying condition will also need treatment. Certain classes of medications that are used to treat migraines or heart disease may constrict blood vessels and may need to be discontinued for a time. In these milder cases, the ischemic colitis may resolve in a few days.

In other, more severe cases, medications such as those that break up blood clots (thrombolytics) and widen the arteries (vasodilators) may be used. If the artery is not clearing, surgery to remove the blockage is another potential treatment, but this is usually only done after other treatments aren’t working. If there is a perforation (hole) in the colon, or a narrowed section (stricture), surgery might be needed to repair these problems. If there is tissue in the colon that has died, surgery will be done to remove that section of the bowel (resection).

A Word From Verywell

Ischemic colitis sounds quite worrying but most cases resolve in a few days without any aggressive treatment. More severe cases may require surgery but most people recover well without complications. Any time there’s a change in bowel habits, such as going to the bathroom more often or less often, it should be discussed with a physician. Blood in the stool or abdominal pain, which is how ischemic colitis often starts, should always prompt a visit to a doctor to find out what’s causing these symptoms.

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