A Meckel diverticulum is a saclike outpouching of the wall of the small intestine that is present in some children at birth.
Most children do not have symptoms, but sometimes painless rectal bleeding occurs or the diverticulum becomes infected.
Doctors base the diagnosis on symptoms, the results of a radionuclide scan, and sometimes other imaging tests.
A bleeding diverticulum or one that causes symptoms must be surgically removed.
About 2 to 3% of infants are born with a Meckel diverticulum.
People can live their whole lives without ever knowing they have a Meckel diverticulum, but occasionally the abnormality causes complications. Although diverticula are equally common among boys and girls, boys are 2 to 3 times more likely to have complications. Complications of Meckel diverticulum include
Over half the time, the diverticulum contains tissue like that of the stomach, pancreas, or both. If stomach tissue is present, it can secrete acid just like the stomach does. This acid may cause ulcers and bleeding of the nearby intestine. Bleeding is more common among children under 5 years of age.
Obstruction can occur at any age but is more common among older children and adults. In children, obstruction is most likely caused by intussusception of the diverticulum.
A Meckel diverticulum may also become inflamed (diverticulitis). Acute Meckel diverticulitis can occur at any age, but older children are most affected.
A perforation (hole) in the diverticulum causes peritonitis, which is a very serious and painful inflammation of the abdominal cavity.
Tumors, including carcinoid tumors, are rare and occur mainly in adults.
Most children with a Meckel diverticulum have no symptoms, and many adults learn they have the condition only after surgeons discover it while doing surgery for another reason. The most common symptom among children younger than 5 years is painless rectal bleeding, which comes from ulcers in the small intestine caused by acid secreted by the diverticulum. Because of the bleeding, stools may appear bright red or brick-colored or currant jelly–colored because of a mixture of blood and mucus. Sometimes, stool appears black because of the breakdown of blood. Only rarely is the bleeding so severe that the child needs emergency surgery.
Diverticulitis caused by a Meckel diverticulum causes severe abdominal pain, abdominal tenderness, and vomiting and can easily be confused with appendicitis.
It is often difficult for doctors to diagnose a Meckel diverticulum.
Blood tests, x-rays, CT, and barium enemas are not usually helpful.
If doctors think bleeding from the rectum is caused by a Meckel diverticulum, they do an imaging study called a Meckel scan. In this study, a small amount of a harmless radioactive substance is given by vein (intravenously). The substance is picked up by cells in the diverticulum, which can then be seen using a radiation-sensing camera. Video capsule endoscopy (in which the child swallows a small camera that can detect sources of bleeding in the small intestine) and double-balloon enteroscopy (in which a small flexible viewing tube is gently passed into the small intestine) are other tests the can help doctors identify a diverticulum as the source of bleeding.
Children who have abdominal pain often undergo a CT scan, which can diagnose a diverticulum and other causes of pain.
No treatment is needed for a diverticulum that does not cause symptoms.
A bleeding diverticulum or one that causes obstruction or ongoing symptoms must be surgically removed.
If a Meckel diverticulum is found in a child during an operation being done for another reason, it may be removed to prevent future complications.