Ischemic colitis occurs when blood flow to part of the large intestine (colon) is reduced due to narrowed or blocked blood vessels (arteries). The diminished blood flow provides insufficient oxygen for the cells in your digestive system. It can cause pain and can damage your colon. Ischemic colitis can affect any part of the colon, but most people experience pain on the left side of the belly area (abdomen).
Ischemic colitis is most common among people older than age 60. It 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 or prevent infection, or surgery if your colon has been damaged.
The precise cause of diminished blood flow to the colon isn’t always clear. But several factors can increase your risk of colon ischemia:
- 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:
- Nonsteroidal anti-inflammatory drugs
- Some heart and migraine medications that shrink blood vessels
- Hormone medications, such as estrogen
- Certain medications for irritable bowel syndrome
- Chemotherapy medications
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. When blood flow is blocked on the right side of your colon, it’s likely that flow is blocked to part of your small intestine as well. 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.