Understanding Meckel's Diverticulum: A Comprehensive Clinical Guide to the Most Common Congenital GI Anomaly

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Meckel's Diverticulum, the most prevalent congenital anomaly of the gastrointestinal tract, remains a "great masquerader" in clinical practice. Often asymptomatic, it can present with life-threatening complications such as massive gastrointestinal bleeding, intussusception, or diverticulitis, mimicking acute appendicitis. This column explores the intricate details of Meckel's Diverticulum diagnosis, Meckel's Diverticulum treatment, and the latest imaging modalities used to identify this vestigial remnant.

Pathophysiology of Meckel's Diverticulum

Meckel's Diverticulum arises from the incomplete obliteration of the vitelline duct (also known as the omphalomesenteric duct) during the fifth to seventh weeks of gestation. In normal embryonic development, this duct connects the primitive midgut to the yolk sac and should spontaneously involute.

When this process fails, a "true diverticulum" is formed—meaning it contains all four layers of the intestinal wall: mucosa, submucosa, muscularis propria, and adventitia. A critical pathophysiological feature is the presence of ectopic tissue. Approximately 50% of symptomatic cases contain ectopic gastric mucosa, which secretes acid, leading to ulceration of the adjacent ileal mucosa and subsequent painless hematochezia.

Epidemiology and the "Rule of Twos"

Epidemiologically, Meckel's Diverticulum is famously described by the "Rule of Twos":

  • Occurs in 2% of the population.
  • Located approximately 2 feet (60 cm) from the ileocecal valve.
  • Typically 2 inches in length.
  • Contains 2 types of common ectopic tissue (gastric and pancreatic).
  • Often presents before 2 years of age (though it can occur at any age, as seen in the 11-year-old patient case).

Clinical Presentation

The clinical manifestations of Meckel's Diverticulum vary significantly by age. In pediatric populations, the most common presentation is painless lower gastrointestinal bleeding (hematochezia). However, as highlighted in our case study, adolescents and adults may present with:

  • Intussusception: The diverticulum acts as a lead point, causing the bowel to telescope into itself.
  • Diverticulitis: Inflammation mimicking appendicitis.
  • Intestinal Obstruction: Often caused by volvulus around a persistent fibrous band connecting the diverticulum to the umbilicus.

Case Interpretation and Imaging Features

In the provided clinical case, an 11-year-old boy presented with increasing periumbilical pain.

[그림 1] Small Bowel Series: The radiograph demonstrates a contrast-filled blind-ending pouch (arrow) in the distal ileum, which is highly suggestive of Meckel's Diverticulum.

Diagnostic Imaging Modalities

  1. Technetium-99m Pertechnetate Scan (Meckel’s Scan): This is the gold standard for detecting ectopic gastric mucosa. However, it may yield a false negative if ectopic tissue is absent, as seen in this specific case.
  2. Computed Tomography (CT): Useful for identifying complications like intussusception or inflammatory changes.
  3. Small Bowel Series: Highly effective in visualizing the diverticulum when nuclear scans are negative.

[그림 2] Laparoscopic View: Surgical visualization reveals a diverticulum on the antimesenteric border of the terminal ileum (arrows) with a visible remnant of the vitelline artery (arrowhead).

Differential Diagnosis

When evaluating Meckel's Diverticulum symptoms, clinicians must rule out:

  • Acute Appendicitis: Often indistinguishable from Meckel’s diverticulitis.
  • Crohn’s Disease: Can cause similar terminal ileum inflammation.
  • Intussusception (Idiopathic): Common in younger children but usually lacks a lead point.
  • Peptic Ulcer Disease: Considered if upper GI bleeding is suspected.

Treatment and Prognosis

The definitive Meckel's Diverticulum treatment is surgical resection.

  • Diverticulectomy: Simple removal of the pouch.
  • Segmental Resection: Necessary if there is evidence of ulceration in the adjacent ileum or if the base of the diverticulum is wide.

The prognosis is excellent following surgical intervention, with a very low rate of recurrence or long-term complications.

Quiz

Question 1: A 10-year-old child presents with periumbilical pain and signs of proximal small bowel intussusception on CT. A Technetium-99m scan is negative. What is the most likely diagnosis based on the provided small bowel series image?

A) Hirschsprung's disease

B) Meckel's diverticulum

C) Situs inversus

D) Pyloric outlet obstruction

Answer: B) Meckel's diverticulum. Explanation: The image shows a classic blind-ending pouch in the ileum. A negative Meckel's scan does not rule out the diagnosis, as ectopic gastric mucosa is not always present.


Question 2: Regarding the pathophysiology of Meckel's Diverticulum, which embryonic structure failed to involute?

A) Urachus

B) Vitelline duct

C) Mullerian duct

D) Cardinal vein

Answer: B) Vitelline duct. Explanation: Meckel's diverticulum is a remnant of the vitelline (omphalomesenteric) duct.


Question 3: What is the "Rule of Twos" regarding the location of Meckel's Diverticulum?

A) 2 cm from the stomach

B) 2 feet from the ileocecal valve

C) 2 meters from the ligament of Treitz

D) 2 inches from the appendix

Answer: B) 2 feet from the ileocecal valve. Explanation: Standard anatomical location is within 2 feet (60cm) of the ileocecal valve on the antimesenteric border.

References

1. Levy, A. D., & Hobbs, C. M. (2010). Meckel Diverticulum. New England Journal of Medicine, 362(22), e67. DOI: 10.1056/NEJMicm1001158.

2. Sagar, J., et al. (2006). Meckel's diverticulum: a systematic review. Journal of the Royal Society of Medicine.

3. Hansen, C. C., & Søreide, K. (2018). Systematic review of epidemiology, presentation, and management of Meckel's diverticulum. British Journal of Surgery.

4. Kotecha, M., et al. (2012). Multimodality imaging of Meckel's diverticulum and its complications. Radiographics.

5. Malik, A. A., et al. (2008). Meckel's diverticulum—Revisited. International Journal of Surgery.

6. Rattan, K. N., et al. (2016). Meckel's diverticulum in children: A 25-year experience. African Journal of Paediatric Surgery.

7. Srisajjakul, S., et al. (2019). Multidetector CT of Meckel's diverticulum and its complications. Japanese Journal of Radiology.

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