The mesenteric arteries supply blood to your large and small intestines. Ischemia occurs when your blood cannot flow through your arteries as well as it should, and your intestines do not receive the necessary oxygen to perform normally. Mesenteric ischemia usually involves the small intestine, but it may also involve other intra-abdominal organs such as the colon, liver, and stomach.
Mesenteric ischemia usually occurs when one or more of your mesenteric arteries narrows or becomes blocked. When this blockage occurs, you can experience severe abdominal pain. Over time, often quickly, the blockage may worsen and cause tissues in your intestine to die because they lack enough blood flow.
Mesenteric ischemia usually occurs in people older than age 60. You may be more likely to experience mesenteric ischemia if you are a smoker or have a high cholesterol level.
Mesenteric ischemia can be either chronic or acute. Chronic means that you have had the condition and symptoms over a relatively long period of time. Acute means that the symptoms start abruptly and become very serious in a short period of time. Chronic mesenteric ischemia can progress without warning to acute mesenteric ischemia, sometimes very quickly.
WHAT ARE THE SYMPTOMS OF CHRONIC MESENTERIC ISCHEMIA?
If you have chronic mesenteric ischemia, you may experience severe pain in your abdomen 15 to 60 minutes after you eat. This pain can occur in any part of the abdomen, but most commonly it occurs in the middle to upper part. The pain may last for as long as 60 to 90 minutes and then disappear. Unfortunately, it tends to return the next time you eat.
Many people with chronic mesenteric ischemia begin losing weight because, although they may feel hungry, they do not want to eat because they experience the pain.
Sometimes the symptoms of chronic mesenteric ischemia can be vague and can be similar to those of other conditions. Therefore, your physician will evaluate you and order tests to rule out other problems before making a definite diagnosis.
In addition to abdominal pain and weight loss, other symptoms that you might experience include:
With acute mesenteric ischemia, you may have sudden, severe stomach pain. Narcotic pain medications may not adequately alleviate the pain that is associated with mesenteric ischemia. With acute mesenteric ischemia, you may also experience nausea or vomiting.
WHAT CAUSES MESENTERIC ISCHEMIA?
Atherosclerosis, which slows the amount of blood flowing through your arteries, is a frequent cause of chronic mesenteric ischemia. Your arteries are normally smooth and unobstructed on the inside, but as you age, a substance called plaque forms in the walls of your arteries.
Plaque is made of fats and other materials circulating in your blood. As more plaque builds up, your arteries can narrow and stiffen. Eventually, enough plaque builds up to reduce blood flow through your arteries.
A clot, called an embolus, which travels to one of the mesenteric arteries and suddenly blocks the blood flow, is a common cause for acute mesenteric ischemia. These clots often originate in the heart and are more common among patients with an irregular heartbeat or heart disease.
Other conditions that may lead to mesenteric ischemia include:
- Low blood pressure
- Congestive heart failure
- Aortic dissection, which is a tear in the aorta’s inner layer
- Occlusion or blockage of the veins in the bowel
- Coagulation disorders
- Unusual disorders of the blood vessels such as fibromuscular dysplasia and arteries