Meckel’s diverticulum is a small pocket in the wall of the intestine, near the junction of the small and large intestines. The pouch is a remnant of tissue from the prenatal development of the digestive system. It is not made of the same type of tissue as the small intestine, but, instead, is made of the type of tissue found in the stomach or the pancreas.
The tissue in Meckel’s diverticulum produces acid, just as the tissue of the stomach does. The intestinal lining is not familiar to acid and thus, an ulcer can form over time. The ulcer can rupture, causing waste products from the intestine to leak into the abdominal cavity. A serious abdominal infection called peritonitis can result. The intestine can also become blocked by Meckel’s diverticulum, which can prevent the passage of digested food and lead to intestinal obstruction.
Most people who have a Meckel’s diverticulum have no symptoms or problems. Only about 1 in 25 persons who are born with it will have problems. These problems vary by age. In infants and children, the problem is usually bleeding from the rectum. Sometimes blood can be seen in the stool.
In adults, the intestine may become blocked. If this happens, the person may have stomach pain and vomiting. Other symptoms include fever, constipation and swelling of the stomach.
Most cases of Meckel’s diverticulum are discovered incidentally during laparotomy procedures. Symptomatic cases present a diagnostic challenge. Common presenting features in symptomatic patients include melena, rebound tenderness, and right lower-quadrant pain. In patients presenting with a symptomatic Meckel’s diverticulum, the initial differential diagnosis is broad, because of the relative infrequency of this condition and the extensive overlap with other GI disorders. For example, in patients presenting with GI bleeding, other lesions must be considered first, such as bleeding ulcers or bleeding colonic diverticula, depending on the type of GI bleeding noted (eg, melena versus hematemesis versus bright-red blood from the rectum).
In patients presenting with peritoneal signs, colonic diverticulitis, appendicitis, or other hollow viscus perforation must be considered first.
Meckel’s diverticulum should be suspected when the initial diagnostic workup has failed to demonstrate these abnormalities or has revealed abnormalities in an unsuspected location, such as a bleeding vessel located in the ileum seen on angiography or inflammation with or without free air located in the midileum seen on a CT scan.