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Meckel's diverticulum (ileal diverticulum)

persistence of the vitelline duct Epidemiology: 1) the most frequent developmental abnormality of the gut - 1-2 % of population 2) accounts for 50% of cases of lower GI bleeding in children & young adults 3) male:female ratio is 3:1 [6] Pathology: - persistence of the vitelline duct, manifesting as a pouch like remnant (3-6 cm long) - found within 100 cm (typically within 50 cm in adults & 40 cm in infants) of the ileocecal valve on the anti-mesenteric] border of the ileum - contains all layers of mucosa, thus is a true diverticulum - mucosa is generally ileal, but may be gastric - acid-producing ectopic gastric mucosa in the diverticulum may lead to development of an ulcer in adjacent normal mucosa - may be attached to the umbilicus (26%) or free (74 %) Clinical manifestations: - generally painless [6] - no palpable mass [6] - hematochezia - may become inflamed & produce pain that may mimic that of appendicitis Laboratory: - complete blood count if evidence of GI bleed Special laboratory: - upper GI endoscopy is normal Radiology: 1) generally not helpful 2) technetium-99m scan (gastric parietal cells concentrate technetium-99m) may show the diverticulum Complications: 1) hemorrhage resulting from ileal mucosa adjacent to gastric mucosa - profuse BRBPR may be reported [6] 2) small bowel obstruction due to intussusception & volvulus around the band fixing the diverticulum to the bowel wall 3) benign leiomyomas & malignant carcinoids & leiomyosarcomas within the diverticulum 4) diverticulitis is uncommon 5) incarceration in an indirect inguinal hernia 6) perforation with peritonitis Differential diagnosis: - inflammatory bowel disease - likely symptomatic, abdominal pain & tenderness - extra-intestinal manifestations - Crohn's disease - non-bloody diarrhea - megaloblastic anemia - RLQ abdominal mass Management: - surgery should remove all ectopic mucosa [5] - diverticulectomy for a diverticulum with a narrow base - wedge or segmental resection for a diverticulum with a broad base [5]

Related

vitelline duct (yolk stalk, umbilical duct, omphalomesenteric duct)

General

developmental disorder diverticulum

References

  1. Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999.
  2. Grant's Atlas of Anatomy, 10th edition, AMR Agur & MJ Lee (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.
  3. Clinically Oriented Anatomy, 4th edition, KL Moore & AF Dalley (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.
  4. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 299
  5. Rothaus C A Boy with Gastrointestinal Bleeding. Resident 360. Mar 29, 2017. https://resident360.nejm.org/content_items/2525/
  6. NEJM Knowledge+ Gastroenterology

Images

image related to Meckel's diverticulum