Ischemic colitis occurs when blood flow to part of the large intestine (colon) is reduced, usually due to narrowed or blocked blood vessels (arteries). The diminished blood flow doesn't provide enough oxygen for the cells in your digestive system.
Ischemic colitis can cause pain and may damage your colon. Any part of the colon can be affected, but ischemic colitis usually causes pain on the left side of the belly area (abdomen).
The condition can be misdiagnosed because it can easily be confused with other digestive problems. Ischemic colitis may heal on its own. But you may need medication to treat ischemic colitis or prevent infection, or you may need surgery if your colon has been damaged.
Symptoms of the ischemic colitis
Signs and symptoms of ischemic colitis can include:
- Pain, tenderness or cramping in your belly, which can occur suddenly or gradually
- Bright red or maroon-colored blood in your stool or, at times, passage of blood alone without stool
- A feeling of urgency to move your bowels
The risk of severe complications is higher when you have symptoms on the right side of your abdomen. That's because the arteries that feed the right side of your colon also feed part of your small intestine, and may be blocked too. Pain tends to be more severe with this type of ischemic colitis.
Blocked blood flow to the small intestine can quickly lead to death of intestinal tissue (necrosis). If this life-threatening situation occurs, you'll need surgery to clear the blockage and to remove the portion of the intestine that has been damaged.
When to see a doctor
Seek immediate medical care if you have sudden, severe abdominal pain. Abdominal pain that makes you so uncomfortable that you can't sit still or find a comfortable position is a medical emergency.
Contact your doctor if you develop worrisome signs and symptoms, such as bloody diarrhea. Early diagnosis and treatment can help prevent serious complications.
Causes of the ischemic colitis
The precise cause of diminished blood flow to the colon isn't always clear. But several factors can increase your risk of ischemic colitis:
- Buildup of fatty deposits on the walls of an artery (atherosclerosis)
- Dangerously low blood pressure (hypotension) associated with heart failure, major surgery, trauma or shock
- A blood clot in an artery supplying the colon or, less commonly, in a vein (venous thrombosis)
- Bowel obstruction caused by a hernia, scar tissue or a tumor
- Surgery involving the heart or blood vessels, or the digestive or gynecological systems
- Other medical disorders that affect your blood, such as inflammation of the blood vessels (vasculitis), lupus or sickle cell anemia
- Cocaine or methamphetamine use
- Colon cancer (rare)
The role of medications
Certain medicines also can lead to ischemic colitis, though this is rare. They include:
- Some heart and migraine medications
- Hormone medications, such as estrogen
- Certain medications for irritable bowel syndrome
- Chemotherapy medications
Risk factors for ischemic colitis include:
- Age. The condition occurs mostly frequently in adults older than age 60. Ischemic colitis that occurs in a young adult may be a sign of a blood-clotting abnormality or inflammation of the blood vessels (vasculitis).
- Clotting abnormalities. Conditions that affect the way the blood clots, such as Factor V Leiden, may increase the risk of ischemic colitis.
- High cholesterol, which can lead to atherosclerosis.
- Reduced blood flow, due to heart failure, low blood pressure and shock.
- Previous abdominal surgery. Scar tissue that forms after surgery may cause reduced blood flow.
- Heavy exercise, such as marathon running, which can lead to reduced blood flow to the colon.
- Surgery involving the large artery (aorta) that pumps blood from your heart to the rest of your body.
Tests and diagnosis of the ischemic colitis
Ischemic colitis can often be confused with other disorders because their symptoms overlap, especially inflammatory bowel disease (IBD). Based on your signs and symptoms, your doctor may recommend these imaging tests:
- Ultrasound and abdominal CT scans, to provide images of your colon that can be helpful in ruling out other disorders, such as IBD.
- Stool analysis, to rule out infection as a cause of your symptoms.
- CT or MRI angiography, to provide detailed images of blood flow in your small intestine and to look for blocked arteries. This test is usually used only if ischemia is suspected in your small bowel as well as in your colon.
- Colonoscopy. This test, which provides detailed images of your colon, can be helpful in diagnosing ischemic colitis. Colonoscopy can also be used to check for cancer, and to see how well a treatment worked.