Intestinal ischemia occurs when the blood flow to your intestines is slowed or stopped. Due to the diminished blood flow, the cells in your digestive system are starved for oxygen, and can become weak and die, damaging your intestines.

Intestinal ischemia is often divided into categories:

Colon ischemia (ischemic colitis)

Colon ischemia occurs when blood flow to the colon is slowed. It is the most common type of intestinal ischemia. Colon ischemia usually affects adults over age 60, but may occur at any age.

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
  • 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
  • Some medications, especially those that shrink blood vessels, such as some heart and migraine medications, and hormone medications, such as estrogen
  • Cocaine or methamphetamine use

Acute mesenteric ischemia

Acute mesenteric ischemia affects the small intestine. It comes on abruptly and may be due to:

  • A blood clot that blocks an artery leading to your small intestine. Blood clot is the most common cause of acute mesenteric ischemia, and can result from congestive heart failure, an irregular heartbeat (arrhythmia) or a heart attack.
  • A blockage in an intestinal artery that slows or stops blood flow, often as a result of the buildup of fatty deposits along the wall of an artery (atherosclerosis). A blocked intestinal artery is often the cause of chronic mesenteric ischemia that later becomes acute.
  • Low blood pressure due to shock, heart failure, certain medications or chronic kidney failure. Low blood pressure can reduce blood flow to the small intestine. This cause is more common in people with other serious illnesses or some degree of atherosclerosis. This type of acute mesenteric ischemia is sometimes called nonocclusive ischemia.

Chronic mesenteric ischemia

Chronic mesenteric ischemia, also called intestinal angina, results from the gradual buildup of fatty deposits along the wall of an artery (atherosclerosis). Chronic mesenteric ischemia can progress to acute mesenteric ischemia, especially if a blood clot develops within a diseased artery.

Mesenteric venous thrombosis

This type of intestinal ischemia occurs when a blood clot develops in the vein that carries blood away from the intestines. The blocked vein causes blood to back up into the intestines, leading to swelling and bleeding. Mesenteric venous thrombosis may result from:

  • Acute or chronic inflammation of the pancreas (pancreatitis)
  • Abdominal infection
  • Cancers of the digestive system
  • Bowel diseases, such as ulcerative colitis, Crohn's disease or diverticulitis
  • Disorders that make your blood more prone to clotting (hypercoagulation disorders), such as an inherited protein deficiency
  • Trauma to your abdomen
  • Some hormone therapy
Aug. 17, 2012