Meckel's diverticula

Epidemiology

Remnant of proximal vitelline (omphalomesenteric) duct (connects embryonic midgut to the yolk sac). Results from incomplete closure.
Lined by pluripotent cells - therefore, can find heterotopic tissue inside
- Usually normal ileal mucosa
- Gastric mucosa in 50%
- Pancreatic mucosa in 5%
- Colonic mucosa rarely
Projects from antimesenteric border 45-60cm from ICV.
Ranges from a small bump to a long projection communicating with the umbilicus
Typically about 5cm long and 2cm wide
Rule of twos:
- 2 feet from ICV
- 2% of population
- Symptomatic in 2% of cases (usually within first 2 years of life)
- Usually less than two inches/5cm in length

Mostly benign and incidentally discovered during autopsy, laparotomy or barium study
Bleeding - most common presentation
- Can be acute massive bleed, anaemia secondary to occult bleed, or a self-limited recurrent episodic event
- Usual source of bleeding is a chronic acid-induced ulcer in the ileum adjacent to a Meckel diverticulum that contains gastric mucosa
Obstruction is also common
- Can result from volvulus of small bowel, intussusception, or rarely incarceration of diverticulum in an inguinal hernia (Littre hernia)
- Should resect in all cases
Diverticulitis (10-20% of symptomatic presentations)
- More common in adults - clinically indistinguishable from appendicitis
- Can lead to perforation
- Should always look for a Meckel's when the appendix is found to be normal
Neoplasms
- NET (77%)
- Adenocarcinoma (11%)
- GIST (10%)
- Lymphoma (1%)

AXR, CT and USS are rarely helpful
Sodium 99m-Tc-pertechnetate scintigraphy
- Especially useful in children
- Molecule is preferentially taken up by mucus-secreting cells of gastric mucosa and ectopic gastric tissue in the diverticulum
- Sensitivity 85%, specificity 95% in children
- Sensitivity 63% in adults due to less presence of gastric mucosa in the diverticulum - also need to pre-treat with cimetidine to increase uptake
Barium contrast imaging
CT angio - in patients with bleeding