Colon and small intestine
The small intestine and colon are components of your digestive tract, which processes the foods you eat. The intestines extract nutrients from the foods. What isn't absorbed by the intestines continues along the digestive tract and is expelled as stool during a bowel movement. Diarrhea can be present due to abnormalities in the small intestine or the large intestine.
Intestinal ischemia (is-KEE-me-uh) describes a variety of conditions that occur when blood flow to your intestines decreases due to a blocked blood vessel, usually an artery. Intestinal ischemia can affect your small intestine, your large intestine (colon) or both.
Intestinal ischemia is a serious condition that can cause pain and make it difficult for your intestines to work properly. In severe cases, loss of blood flow to the intestines can damage intestinal tissue and possibly lead to death.
Treatments are available for intestinal ischemia. To improve the chances of recovery, it's crucial to recognize the early symptoms and get medical help right away.
Signs and symptoms of intestinal ischemia can develop suddenly (acute) or gradually (chronic). Signs and symptoms may be different from one person to the next, but there are some generally recognized patterns that suggest intestinal ischemia.
Symptoms of acute intestinal ischemia
Signs and symptoms of acute intestinal ischemia typically include:
- Sudden abdominal pain that may be mild, moderate or severe
- An urgent need to have a bowel movement
- Frequent, forceful bowel movements
- Abdominal tenderness or distention
- Blood in your stool
- Mental confusion in older adults
Symptoms of chronic intestinal ischemia
Signs and symptoms of chronic intestinal ischemia can include:
- Abdominal cramps or fullness, usually within 30 minutes after eating, and lasting one to three hours
- Abdominal pain that gets progressively worse over weeks or months
- Fear of eating because of subsequent pain
- Unintended weight loss
When to see a doctor
Seek immediate medical care if you have sudden, severe abdominal pain. Pain that makes you so uncomfortable that you can't sit still or find a comfortable position is a medical emergency.
If you have other signs or symptoms that worry you, make an appointment with your doctor.
Intestinal ischemia occurs when the blood flow through the major arteries that supply blood to your intestines slows or stops. The condition has many potential causes, including a blockage in an artery caused by a blood clot, or a narrowing of an artery due to buildup of deposits, such as cholesterol. Blockages also can occur in veins, but they're less common.
Intestinal ischemia is often divided into categories:
Colon ischemia (ischemic colitis)
This type of intestinal ischemia, which is the most common, occurs when blood flow to the colon is slowed. The cause of diminished blood flow to the colon isn't always clear, but a number of conditions can make you more vulnerable to colon ischemia:
- Dangerously low blood pressure (hypotension) associated with heart failure, major surgery, trauma or shock
- A blood clot in an artery supplying the colon
- Twisting of the bowel (volvulus) or trapping of intestinal contents within a hernia
- Excessive bowel enlargement from bowel obstruction caused by scar tissue or a tumor
- Other medical disorders that affect your blood, such as inflammation of your blood vessels (vasculitis), lupus or sickle cell anemia
- Medications that constrict blood vessels, such as some used to treat heart disease and migraine
- Hormonal medications, such as birth control pills
- Cocaine or methamphetamine use
- Vigorous exercise, such as long-distance running
Acute mesenteric ischemia
This type of intestinal ischemia usually affects the small intestine. It has an abrupt onset and may be due to:
- A blood clot (embolus) that dislodges from your heart and travels through your bloodstream to block an artery, usually the superior mesenteric artery, which supplies oxygen-rich blood to your intestines. This is the most common cause of acute mesenteric artery ischemia and can be brought on by congestive heart failure, an irregular heartbeat (arrhythmia) or a heart attack.
- A blockage that develops within one of the main intestinal arteries and slows or stops blood flow, often as a result of fatty deposits (atherosclerosis) building up on the wall of an artery. This type of sudden ischemia tends to occur in people with chronic intestinal ischemia.
- Impaired blood flow resulting from low blood pressure due to shock, heart failure, certain medications or chronic kidney failure. This is more common in people who have other serious illnesses and who have some degree of atherosclerosis. This type of acute mesenteric ischemia is often referred to as nonocclusive ischemia, which means that it's not due to a blockage in the artery.
Chronic mesenteric ischemia
Chronic mesenteric ischemia, also known as intestinal angina, results from the buildup of fatty deposits on an artery wall (atherosclerosis). The disease process is generally gradual, and you may not require treatment until at least two of the three major arteries supplying your intestines become severely narrowed or completely obstructed.
A potentially dangerous complication of chronic mesenteric ischemia is the development of a blood clot within a diseased artery, causing blood flow to be suddenly blocked (acute mesenteric ischemia).
Ischemia that occurs when blood can't leave your intestines
A blood clot can develop in a vein draining deoxygenated blood from your intestines. When the vein is blocked, blood backs up in the intestines, causing swelling and bleeding. This is called mesenteric venous thrombosis, and it may result from:
- Acute or chronic inflammation of your 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 clotting disorder
- Medications such as estrogen that can increase clotting risk
- Abdominal injuries
Factors that may increase your risk of intestinal ischemia include:
- Buildup of fatty deposits in your arteries (atherosclerosis). If you've had other conditions caused by atherosclerosis, such as decreased blood flow to your heart (coronary artery disease), legs (peripheral vascular disease) or the arteries serving your brain (carotid artery disease), you have an increased risk of intestinal ischemia.
- Age. People older than 50 are more likely to develop intestinal ischemia.
- Smoking. Cigarettes and other forms of smoked tobacco increase your risk of intestinal ischemia.
- Chronic obstructive pulmonary disease. Emphysema and other smoking-related lung diseases increase your risk of intestinal ischemia.
- Heart problems. Your risk of intestinal ischemia is increased if you have congestive heart failure or an irregular heartbeat such as atrial fibrillation.
- Medications. Certain medications may increase your risk of intestinal ischemia. Examples include birth control pills and medications that cause your blood vessels to expand or contract, such as certain allergy medications and migraine medications.
- Blood-clotting problems. Diseases and conditions that increase your risk of blood clots may increase your risk of intestinal ischemia. Examples include sickle cell anemia and the Factor V Leiden mutation.
- Illegal drug use. Cocaine and methamphetamine use have been linked to intestinal ischemia.
Complications of intestinal ischemia can include:
- Death of intestinal tissue. If blood flow to your intestine is completely and suddenly blocked, intestinal tissue can die (gangrene).
- Perforation. A hole through the wall of the intestines can develop. This results in the contents of the intestine leaking into the abdominal cavity, causing a serious infection (peritonitis).
- Scarring or narrowing of your colon. Sometimes the intestines can recover from ischemia, but as part of the healing process the body forms scar tissue that narrows or blocks the intestines.
In some cases, intestinal ischemia is fatal.