What is Meckel's Diverticulum?
Meckel's diverticulum is a small outpouching extending from the wall of the intestine and located in the lower portion of the small intestine. The pouch is a remnant of tissue from the embryonic development of the digestive system. The lining of this pouch is made up of either pancreatic tissue or acid-secreting tissue such as that seen in the stomach.
While Meckel's diverticulum is the most common congenital (present at birth) abnormality of the digestive system (present in 2% of the population), most people with this abnormality do not develop symptoms or problems. However, in some individuals, the secretion of acid by Meckel's diverticulum may cause ulcers in the small intestinal lining. These ulcers can bleed or perforate (split open), causing intestinal waste products to leak into the abdomen. This can result in a serious abdominal infection called peritonitis.
Meckel's diverticulum can also cause intestinal obstruction. It can do this by folding in on itself into the passageway of the intestine (called intussusception), or a portion of small intestine may also twist around an anchored Meckel's diverticulum. This is known as segmental volvulus and can be associated with compromised blood supply to the bowel.
Reasons for Concern
When the intestine develops an ulcer, significant bleeding can occur, resulting in anemia (low red blood cell count). Rapid blood loss can be associated with shock, which is life-threatening. Intestinal obstruction and serious infection may also occur.
Risk Factors for Meckel's Diverticulum
Complications from Meckel's diverticulum can develop at any age, and it is estimated that there is a 4% to 25% lifetime risk of complications occurring. However, this risk decreases with age. Infants and children appear to be at highest risk for complications, with more than 50% of symptomatic Meckel's diverticula occurring in children less than 2 years of age.
An increased incidence of Meckel's diverticula is seen in association with other congenital anomalies, including esophageal atresia, imperforate anus (anorectal malformations), omphalocele, Crohn's disease, and various neurological and cardiovascular malformations.
Signs and Symptoms of Meckel's Diverticulum
Symptoms occur only if the diverticulum bleeds, becomes infected or causes an obstruction, and they are twice as common in males than in females. The symptom most commonly seen in young children is painless rectal bleeding. The color of blood may vary from bright red (35%) to dark red or maroon (40%) to black/tarry (7%).
While symptoms of infection and blockage generally occur before adolescence, they can appear at any time in life and can cause mild to severe abdominal pain and discomfort.
Diagnosis of Meckel's Diverticulum
Rectal bleeding requires a systematic approach to evaluation. When patients are stable and when bleeding is slow or episodic, a variety of tests may be performed.
- Blood test: This is done to determine if anemia or infection is present. A stool sample may also be obtained to check for frank (obvious) or occult (hidden) blood.
- Meckel's scan: A radioactive substance called technetium is injected into the bloodstream through an intravenous (IV) line. This substance can be seen on X-rays and indicates areas where acid-secreting stomach tissue exists, including that seen in the Meckel's diverticulum.
- Colonoscopy: A small, flexible tube with a camera on the end is inserted into the colon (last part of the intestine). The inside of the rectum and large intestine are evaluated for bleeding, blockage and other problems.
With significant and ongoing blood loss, additional tests such as bleeding scan, colonoscopy, and angiography may be performed. In rare cases, life-threatening blood loss may necessitate urgent exploratory surgery.
Treatment for Meckel's Diverticulum
A symptomatic Meckel's diverticulum should be resected (removed) with an operation. This operation can be performed using either an open or a laparoscopic surgical approach. With both approaches, Meckel's diverticulum is resected, the ulcerated area is identified, and the bleeding is stopped.
As with other gastrointestinal surgical procedures, possible postoperative complications include a small risk of wound infection and developing adhesions later in life.
Long-Term Outlook
After recovery, removal of Meckel's diverticulum generally has no effect on gastrointestinal functioning or nutrition.
