Acute mesenteric ischemia is sudden blockage of blood flow to part of the intestines, which may lead to gangrene and perforation (puncture).
Severe abdominal pain develops suddenly.
The diagnosis may be made by angiography.
Immediate treatment is needed using angioplasty or surgery.
(See Overview of Gastrointestinal Emergencies.)
Acute mesenteric ischemia has multiple causes. The most common are
Arterial embolism
Arterial thrombus
Arterial embolism is a blood clot or piece of atherosclerotic plaque material (the buildup of cholesterol and other fatty materials in an artery) that travels from its origin in the heart or aorta to lodge in the smaller arteries (in this case those of the intestines).
Arterial thrombus is a blood clot that forms spontaneously in the arteries or veins, including those of the intestines, blocking flow.
Sometimes flow is not blocked completely but is simply too low because of low heart output (as in heart failure or shock) or because certain medications (such as epinephrine) or drugs (such as cocaine) that narrow the blood vessels. In general, people older than 50 years are at greatest risk.
Blockage of blood flow for more than 6 hours can cause the affected area of intestine to die, allowing intestinal bacteria to invade the person's system. Shock, organ failure, and death are likely if intestinal death occurs.
Symptoms of Acute Mesenteric Ischemia
At first, the person has severe abdominal pain that usually develops suddenly. However, the person usually has only mild pain when the doctor presses on the abdomen during the examination (unlike in disorders such as appendicitis or diverticulitis, in which pressing makes the pain much worse).
Later, as the intestine starts to die, the doctor's examination of the abdomen causes more severe pain.
Diagnosis of Acute Mesenteric Ischemia
A doctor's examination
Angiography
If the person has typical symptoms of acute mesenteric ischemia or if the abdomen is very tender, doctors usually take the person right to surgery.
If the diagnosis of acute mesenteric ischemia is not clear, doctors do CT angiography or mesenteric angiography to look for blockages in the arteries that supply blood to the intestines. In CT angiography, CT (computed tomography) and a radiopaque contrast agent (dye) that is injected in an arm vein are used to produce images of blood vessels. In mesenteric angiography, a small flexible tube (catheter) is threaded through the artery in the groin and into the arteries of the intestines. A radiopaque contrast agent is injected through the catheter to make the arteries easier to see on x-rays that are taken at the same time. Magnetic resonance angiography is another kind of angiography that may be done to provide detailed images of blood vessels.
X-rays or magnetic resonance imaging (MRI) of the abdomen are other tests that may be done.
Treatment of Acute Mesenteric Ischemia
Fluids and antibiotics
Surgery
Angioplasty and placement of a stent
Medications to prevent clotting
People who have acute mesenteric ischemia are given fluids and antibiotics by vein.
If mesenteric ischemia is diagnosed during surgery, the blood vessel blockage can sometimes be removed or bypassed, but other times the affected intestine must be removed.
If mesenteric ischemia is diagnosed during CT angiography or mesenteric angiography, doctors may try to relieve the blockage in the blood vessels using angioplasty and placement of a stent. In angioplasty, a small flexible tube (catheter) is threaded through the artery in the groin and into the arteries of the intestines, and angiography is done. If a blockage is seen, sometimes it can be opened by injecting certain medications, suctioning out a blood clot using a special angiography catheter, or inflating a small balloon within the artery to widen it and then placing a small tube or manufactured mesh (a stent) to keep it open. If doctors cannot successfully open the blockage using these procedures, the person needs surgery to open the blockage or to remove the affected portion of the intestine.
After recovery, many people need to take a medication to help prevent blood clotting.
Prognosis for Acute Mesenteric Ischemia
If the doctor can make the diagnosis and begin treatment early, people usually recover well.
If the diagnosis is not made or if treatment is not started until some of the affected intestine has died, acute mesenteric ischemia is fatal in many people depending on the cause. People cannot survive if almost all the small intestine dies or is removed.
