Vascular ileus is a type of bowel obstruction. This is an extremely dangerous and diagnostically challenging condition that often results in patient’s death.
The basis of the problem is a stoppage of stool passage through the intestines. In this case, however, it is not caused by an obstacle. A part of the intestine stops moving because it has lost its blood supply. The most common cause is formation of a blood clot (thrombus) in a blood vessel supplying the intestine or an obstruction by a blood clot travelling from a distant vessel (embolus). Both conditions have the same result – a sudden arterial closure.
Although the intestinal wall is filled with many small arteries, all these are branches of only two main arteries supplying both small and large intestine. These two arteries are direct branches of aorta – upper mesenteric artery and lower mesenteric artery. Upper mesenteric artery supplies practically the whole small intestine and the first half of the colon. Lower mesenteric artery supplies the second half of the colon including part of the rectum.
The arterial occlusion results in abrupt and shocking abdominal pain that may slowly partly disappear but it is still evident and worsens during abdominal palpation and percussion. An intestinal section without proper blood supply looses peristalsis and that is followed by paralytic ileus. Red blood in stool is often present in the acute phase. As the intestine does not work, vomiting can occur and intestinal bacteria can easily penetrate into abdominal cavity causing peritonitis and sepsis with possibly fatal shock condition.
Examination by a skilled abdominal surgeon is essential. The proper suspicion may be based on symptoms, medical history and cautious physical examination with focusing on the abdomen. Digital rectal examination should always be performed. Simple abdominal X-ray may show signs of ileus – dilated bowel loops containing air and fluid levels. The closure of any large abdominal arteries may be diagnosed by a Doppler ultrasonography and more precisely by direct angiography of intestinal arteries.
The blood clot can be removed by an endovascular or surgical intervention. It the affected intestine is still viable, this procedure is sufficient. Necrotic part of an intestine must be surgically removed. A loss of too big part of the intestine may cause short bowel syndrome and this situation may be sometimes incompatible with life.