Table of Contents
Overview – Meckel’s Diverticulum
Meckel’s diverticulum is a congenital malformation of the small intestine and the most common congenital anomaly of the gastrointestinal tract. Though usually asymptomatic, it can mimic other acute abdominal conditions such as appendicitis and small bowel obstruction. Clinicians should keep Meckel’s diverticulum in the differential for painless rectal bleeding or unexplained abdominal pain in young children, especially around age two. Understanding its embryological origin, potential complications, and classic “Rule of Twos” is crucial for surgical and emergency assessment.
Definition
- A true congenital diverticulum of the small intestine, located on the antimesenteric border of the ileum.
Aetiology
- Caused by incomplete obliteration of the vitelline duct during embryogenesis.
Morphology / Pathophysiology
- True diverticulum: Involves all layers of the intestinal wall
- Typically arises <2 feet from the ileocecal valve
- Contains ectopic tissue (commonly gastric or pancreatic mucosa), which can lead to ulceration and bleeding
Rule of Twos
- Occurs in 2% of the population
- Usually presents by 2 years old
- Around 2 inches in length
- Found within 2 feet of the ileocecal valve
- May contain 2 types of ectopic mucosa (gastric and pancreatic)
Clinical Features
- Often asymptomatic and found incidentally
- Symptomatic presentation typically occurs at age ~2:
- Painless lower GI bleeding (melena)
- Acute abdominal pain (can mimic appendicitis)
- Signs of intestinal obstruction (e.g. volvulus, intussusception)
- Rarely, may cause peritonitis or sepsis if complicated
Complications
- GI bleeding (from ulceration due to ectopic gastric tissue)
- Small bowel obstruction
- Diverticulitis
- Torsion and infarction
- Herniation (Littre’s hernia)
Investigations
- Clinical diagnosis often based on history and presentation
- Imaging:
- Ultrasound or CT scan for detection of complications
- Technetium-99m pertechnetate scan (Meckel’s scan) – may detect ectopic gastric mucosa
Management
- Surgical resection is definitive
- Indicated in symptomatic cases
- Incidental cases may be resected depending on risk factors
Summary – Meckel’s Diverticulum
Meckel’s diverticulum is a true congenital outpouching of the small intestine, often diagnosed in early childhood and associated with painless rectal bleeding or small bowel obstruction. While most cases remain asymptomatic, complications such as ulceration, volvulus, or inflammation may require surgical resection. Its characteristic “Rule of Twos” aids in memory and clinical recognition. For broader context, see our Gastrointestinal Overview page.