Meckel's diverticulum is a congenital pouch (diverticulum) approximately two inches in length and located at the lower (distal) end of the small intestine. It was
named for Johann F. Meckel, a German anatomist who first described the structure.
Description
The diverticulum is most easily described as a blind pouch that is a remnant of the omphalomesenteric duct or yolk sac that nourished the early embryo. It contains all layers of the intestine and may have ectopic tissue present from either the pancreas or stomach.
The rule of twos is the classical description. It is located about 2 ft from the end of the small intestine, is often about 2 in in length, occurs in about 2% of the population, is twice as common in males as females, and can contain two types of ectopic tissue—stomach or pancreas. Many who have a Meckel's diverticulum never have trouble but those that do present in the first two decades of life and often in the first two years.
There are three major complications that may result from the development of Meckel's diverticulum. The most common problem is inflammation or infection that mimics appendicitis. This diagnosis is defined at the time of surgery for suspected appendicitis. Bleeding caused by ectopic stomach tissue that results in a bleeding ulcer is the second most frequent problem. Bleeding may be brisk or massive. The third potential complication is obstruction due to intussusception, or a twist around a persistent connection to the abdominal wall. This problem presents as a small bowel obstruction, however, the true cause is identified at the time of surgical exploration.
Genetic profile
Meckel's diverticulum is not hereditary. It is a vestigial remnant of the omphalomesenteric duct, an embryonic structure that becomes the intestine. As such, there is no genetic defect or abnormality.
Demographics
Meckel's diverticulum is a developmental abnormality that is present in about 2% of people, but does not always cause symptoms. Meckel's diverticula (plural of diverticulum) are found twice as frequently in men as in women. Complications occur three to five times more frequently in males.
Signs and symptoms
Symptoms usually occur in children under 10 years of age. There may be bleeding from the rectum, pain and vomiting, or simply tiredness and weakness from unnoticed blood loss. It is common for a Meckel's diverticulum to be mistaken for the much more common disease appendicitis. If there is obstruction, the abdomen will distend and there will be cramping pain and vomiting.
Diagnosis
The situation may be so acute that surgery is needed on an emergency basis. This is often the case with bowel obstruction. With heavy bleeding or severe pain, whatever the cause, surgery is required. The finer points of diagnosis can be accomplished when the abdomen is open for inspection during a surgical procedure. This situation is called an acute abdomen.
If there is more time (not an emergency situation), the best way to diagnose Meckel's diverticulum is with a nuclear scan. A radioactive isotope injected into the bloodstream will accumulate at sites of bleeding or in stomach tissue. If a piece of stomach tissue or a pool of blood shows up in the lower intestine, Meckel's diverticulum is indicated.
Treatment and management
A Meckel's diverticulum that is causing discomfort, bleeding, or obstruction must be surgically removed. This procedure is very similar to an appendectomy.
Prognosis
The outcome after surgery is usually excellent. The source of bleeding, pain, or obstruction is removed so the symptoms also disappear. A Meckel's diverticulum will not return.
BOOKS
Aspinall, Richard J., and Simon T. Taylor-Robinson. Mosby's Color Atlas & Text of Gastroenterology. St. Louis: Mosby-Year Book, 2001.
Cousins, Claire, and Ralph Boulton. A Color Handbook of Gastroenterology. New York: McGraw-Hill, 1999.
Isselbacher, Kurt J., and Alan Epstein. "Diverticular, Vascular, and Other Disorders of the Intestine and Peritoneum." In Harrison's Principals of Internal Medicine. New York: McGraw Hill, pp. 1648-1655, 1998.
Lipsky, Martin S., and Richard Sadovsky. Gastrointestinal Problems. Philadelphia: Lippincott Williams & Wilkins Publishers, 2000.
Sanderson, Ian R., and W. Allan Walker. Development of the Gastrointestinal Tract. Hamilton, Ontario, Canada: B. C. Decker, 1999.
Stringer, David A., and Paul S. Babyn. Pediatric Gastrointestinal Imaging and Intervention, 2nd edition. Hamilton, Ontario, Canada: B. C. Decker, 2000.
PERIODICALS
al Mahmeed, T., J. K. MacFarlane, and D. Filipenko. "Ischemic Meckel's diverticulum and acute appendicitis." Canadian Journal of Surgery 43, no. 2 (2000): 146-47.
Arnio, P., and I. S. Salonen. "Abdominal disorders arising from 71 Meckel's diverticulum." Annals of Surgery and Gynecology 89, no. 4 (2000): 281-84.
Heider, R., D. M. Warshauer, and K. E. Behrns. "Inverted Meckel's diverticulum as a source of chronic gastrointestinal blood loss." Surgery 128, no. 1 (2000): 107-08.
Martin, J. P., P. D. Connor, and K. Charles. "Meckel's diverticulum." American Family Physician 61, no. 4 (2000): 1037-42.
Nagler, J., J. L. Clarke, and S. A. Albert. "Meckel's diverticulitis in an elderly man diagnosed by computed tomography." Journal of Clinical Gastroenterology 30, no. (2000): 87-88.
ORGANIZATIONS
American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. (913) 906-6000. <http://www.aafp.org/>, fp@aafp.org.
American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. Fax: (847) 434-8000. kidsdoc@aap.org. <http://www.aap.org/default.htm>.
American College of Gastroenterology. 4900 B South 31st Street, Arlington, VA 22206. (703) 820-7400. Fax: (703) 931-4520. <http://www.acg.gi.org>.
American College of Surgeons. 633 North St. Clair St., Chicago, IL 60611-32311. (312) 202-5000. Fax: (312) 202-5001. postmaster@facs.org. <http://www.facs.org/>.
American Medical Association. 515 N. State Street, Chicago, IL 60610. (312) 464-5000. <http://www.ama-assn.org/>.
