Mesenteric ischemia, which is a chronic condition caused by poor blood supply to the intestines, results from narrowing or blockage in one of the three major arteries supplying blood to the intestines. It can also occur suddenly as a result of a blood clot severely restricting blood flow that may cause sudden abdominal pain and, less often, bloody stools. The lack of oxygen-rich blood can permanently damage the intestines. Hence, this situation requires immediate medical care.
The symptoms of acute mesenteric artery ischemia due to a traveling blood clot include diarrhea, sudden severe abdominal pain and vomiting, while the symptoms of chronic mesenteric artery ischemia caused by hardening of the arteries include abdominal pain after eating and diarrhea.
There are three progressive phases of Mesenteric ischemia. They are the following:
- A hyper active stage occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase;
- A paralytic phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel motility decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam;
- Finally, a shock phase can develop as fluids start to leak through the damaged colon lining. This can result in shock and metabolic acidosis with dehydration, low blood pressure, rapid heart rate, and confusion. Patients who progress to this phase are often critically ill and require intensive care.
Mesenteric artery ischemia is often seen in people who have hardening of the arteries that supply blood to the intestines run directly from the aorta. The condition is more common in smokers and in people with high blood pressure or high blood cholesterol.
Mesenteric ischemia may also be caused by a blood clot, which is called ‘embolus’ and that suddenly blocks one of the mesenteric arteries. The clots usually come from the heart or aorta. These clots are more commonly seen in people with abnormal heart rhythms, such as atrial fibrillation.
The most serious complication of mesenteric artery ischemia is death resulting from lack of blood flow (infarction) in the intestines.
Mesenteric ischemia can only be prevented by lifestyle changes that reduce the risk for narrowing of the arteries, such as: getting regular exercise, following a healthy diet, treating heart rhythm problems, keeping the blood cholesterol and blood sugar under control and quitting smoking.