A 2-year-old boy has had several episodes of painless rectal bleeding. He is thriving and haemodynamically stable, with a normal abdomen and normal rectal examination. Which is an important cause of painless lower GI bleeding in a child to consider?

Answer: D. Meckel's diverticulum

Painless lower GI bleeding in a child

In a young child with painless rectal bleeding who is otherwise well, Meckel's diverticulum is an important cause to consider. Ectopic gastric mucosa within the diverticulum secretes acid, causing ulceration of adjacent ileal mucosa and painless bleeding.

Causes of lower GI bleeding (blood +/- mucus) in children

• Meckel's diverticulum.
• Intussusception (colicky pain, redcurrant-jelly stool).
• Anal fissures; colonic polyps.
• Bleeding disorders/anticoagulants (e.g. haemophilia).
• Cow's milk protein allergy; inflammatory bowel disease.

Meckel's facts

• A true congenital diverticulum (the 'rule of 2s': ~2% of people, ~2 feet from the ileocaecal valve, ~2 inches long, often presents under age 2).
• Can also cause obstruction, diverticulitis or intussusception.

Clinical relevance

In painless paediatric PR bleeding, Meckel's is classically sought (e.g. with a technetium pertechnetate scan), though a bleeding disorder must also be considered.