2 per cent, 2 feet from the ileocaecal valve, 2 inches long, 2 types of ectopic tissue, under 2 years
Mnemonic
The rule of 2s:
- 2 per cent of the population
- 2 feet proximal to the ileocaecal valve
- 2 inches long
- 2 types of ectopic tissue: gastric and pancreatic
- Presents before age 2 in most symptomatic cases
- 2 times commoner in males
It is the persistent remnant of the vitelline (omphalomesenteric) duct, and it is a true diverticulum, containing all layers of the bowel wall, which distinguishes it from the false diverticula of the colon.
Ectopic gastric mucosa secretes acid, causing ulceration and painless rectal bleeding, and it is what makes the technetium-99m pertechnetate (Meckel’s) scan work.
Expansion
- 2 per cent of the population
- 2 feet (about 60 cm) proximal to the ileocaecal valve
- 2 inches (about 5 cm) long
- 2 types of ectopic tissue: gastric and pancreatic
- Usually symptomatic before age 2
- 2:1 male predominance
It is the persistent remnant of the vitelline (omphalomesenteric) duct, on the antimesenteric border of the ileum, and being a true diverticulum, it contains all layers of the bowel wall.
Complications follow from the ectopic tissue and the shape:
- Bleeding - ectopic gastric mucosa ulcerates adjacent ileum; the commonest presentation in children
- Obstruction - from a persistent fibrous band or intussusception
- Diverticulitis - mimics appendicitis
Diagnosis is by technetium-99m pertechnetate scan, which is taken up by gastric mucosa.