Meckel Diverticulum

Meckel diverticulum is true congenital diverticulum found in the small intestines. Its name comes from Johann Friedrich Meckel (1781-1833), a German anatomist, who first described the embryological origin in 1809.

Pathogenesis

• Persistence of intestinal end of omphalomesenteric duct
• Arise from antimesenteric border of small intestine (ileum is most common location)
• Heterotopic tissue
  • Gastric tissue (most common tissue) → most likely to produce symptoms and bleeding
  • Pancreatic tissue → causes inflammation

Presentation

• Bleeding (most common presentation) → ulceration on mesenteric border caused by acid made by ectopic gastric tissue
• Obstruction → intussusception, volvulus, torsion, Littre’s hernia
• Meckel’s diverticulitis
  • Inflammation from luminal obstruction
  • Causes: foreign body, enterolith, inflammatory tissue or tumor

Imaging

• Meckel’s scintigraphy scan (Technetium-99m)
  • Detects gastric mucosa, not pancreatic tissue or hemorrhage
  • More senstive in pediatric patients (85%) compared to adults

Treatment

• Incidental
  • Imaging → observation
  • Intraoperative → observation
    • Indications for surgery
      • Length >2 cm
      • Palpable abnormality
      • Fibrous bands
    • Surgical options
      • Diverticulectomy (preferred)
      • Segmental resection if broad base (>2 cm) or palpable abnormality at base
• Diverticulitis
  • Uncomplicated → diverticulectomy
  • Complicated → segmental resection
    • Indications
      • Perforation
      • Inflamed base
      • Wide base (>⅓ diameter of bowel or neck >2 cm)
• Bleeding
  • Diverticulectomy
  • Segmental resection
    • Indication → ulcer on mesenteric border and occasionally distal to antimesenteric diverticulum

Relevant Information

• True diverticula → involves all layers of the wall (mucosa, muscle, and serosa)
• Rule of 2s
  • Found in 2% of population
  • Found within 2 feet of ileocecal valve
  • Often 2 inches in length
  • Contain two types of ectopic mucosa
    • Gastric
    • Pancreatic 
• Can be complicated by inflammation, perforation, hemorrhage, or obstruction 
• Most common…
  • Cause of painless GI bleeds in pediatric patients
  • Lead point in pediatric intussusception 
• Carcinoid is most common neoplasia

Complications

• Obstruction → usually caused by intussusception or volvulus around abnormal fibrous connection between diverticulum and posterior aspect of umbilicus