Meckel Diverticulum

Basics

Description

  • Most common congenital abnormality of the GI tract
    • Results from incomplete obliteration of the omphalomesenteric duct in distal ileum
  • True diverticula (contains all layers):
    • 50% contain normal ileal mucosa
    • 50% contain either gastric (most common), pancreatic, duodenal, colonic, endometrial, or hepatobiliary mucosa
  • Rule of 2’s:
    • 2% prevalence in general population
    • 2% lifetime risk for complications, decreasing with age
    • Symptoms commonly occur around 2 yr of age:
      • 45% of symptomatic patients <2 yr old
    • Average length 2 in
    • Found within 2 ft of the ileocecal valve
  • Male-to-female ratio approximately equal, but more often symptomatic in males
  • Complications:
    • Obstruction and diverticulitis in adults
    • Hemorrhage and obstruction in children
    • Mean age 10 yr
    • Current mortality rate 0.0001%
    • Occur more frequently in males
  • Obstruction:
    • Diverticulum attached to the umbilicus, abdominal wall, other viscera, or is free and unattached, leading to:
      • Intussusception: Diverticulum is the leading edge
      • Volvulus: Persistent fibrous band leads to bowel rotation
  • Diverticulitis:
    • Opening obstructed, leading to bacterial infection
    • Presents like appendicitis (most common preoperative diagnosis with Meckel diverticulum)

Pediatric Considerations
  • Most common cause of significant lower GI bleeding in children
  • Presents at age <5 yr with episodic painless, brisk, and bright-red rectal bleeding

Etiology

Remnant of the omphalomesenteric duct that typically regresses by week 7 of gestation. The ectopic gastric mucosa can secrete gastric enzymes, leading to erosion of the mucosal wall, resulting in bleeding.

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