gastrointestinal disorders
Meckel Diverticulum
Pathophysiology of Meckel Diverticulum
In early fetal life, the vitelline or omphalomesenteric duct that connects the midgut to the yolk sac is normally obliterated by the 6th week. If the portion connecting to the ileum fails to atrophy, a Meckel diverticulum results. This congenital diverticulum arises from the antimesenteric margin of the intestine and contains all layers of the normal bowel and is thus a true diverticulum. In less than 25% of patients, a Meckel diverticulum also contains heterotopic tissue of the stomach (and thus contains parietal cells that secrete hydrochloric acid), pancreas, or both. Only about 2% of people with Meckel diverticulum develop complications. Although diverticula are equally common among males and females, males are 2 to 3 times more likely to have complications. Complications of Meckel diverticulum include Overview of Gastrointestinal Bleeding None Intestinal Obstruction None Colonic Diverticulitis None Acute Perforation of the Gastrointestinal Tract None Tumors Bleeding is more common among young children (<5 years) and occurs when acid secreted from ectopic gastric mucosa in the diverticulum ulcerates the adjacent ileum. 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. Obstruction may also result from adhesions, volvulus, retained foreign bodies, tumors, or incarceration in a hernia (Littre hernia). Acute Meckel diverticulitis can occur at any age, but its incidence peaks in older children. Perforation causes peritonitis. Tumors, including Overview of Carcinoid Tumors , are rare and occur mainly in adults. 