2025 – PAGE 240 – GASTROENTEROLOGY

PAINLESS RECTAL BLEEDING

Painless rectal bleeding can be due to polyps or Meckel’s diverticulum.

PEARLS: Polyps, fissures, and hemorrhoids have small-volume bleeding. Hemorrhoids usually do not result in streaks of blood on the stool. Meckel’s Diverticulum usually results in large-volume bleeding.

MECKEL’S DIVERTICULUM (AKA MECKELS)

Meckel’s diverticulum is a true diverticulum of the small intestine containing all three layers of bowel wall. It is present at birth and can produce LARGE volumes of PAINLESS rectal bleeding. Diagnose with a Meckel’s scan.

PEARLS: Bleeding is usually red, but CAN be melenic. Painless rectal bleeding due to Meckel’s diverticulum is MUCH more common than bleeding due to polyps.

MNEMONIC: The “Rule of 2s” refers to the fact that 2% of the population have a Meckel’s Diverticulum, most of them are located 2 feet from the ileocecal valve, and most are 2 inches in length.

FYI: The Meckel’s scan is a technetium-99 scan that looks for ectopic gastric or pancreatic cells in the small bowel. These ectopic cells are present in 50% of Meckel’s diverticuli. Technetium scans can also be used to help diagnose a small bowel obstruction and intussusception.

FAMILIAL ADENOMATOUS POLYPOSIS (FAP)

Adenomatous (adenomas) polyps are extremely rare in children less than 10 years of age unless you have familial adenomatous polyposis (FAP), an autosomal dominant disorder. Adenomas are not cancerous, but can be precursor lesions to colon cancer. If a child younger than 10 is noted to have a polyp (possibly after presenting for painless rectal bleeding), resect and send for pathology. If the polyp is adenomatous, obtain GENETIC TESTING for the APC mutation (Adenomatous Polyposis Coli mutation). Children with FAP have a 100% chance of ending up with cancer. For APC+ patients, screen for colonic adenomas every year starting at 10 years of age. In order to prevent cancer, the colon is resected once large adenomas (> 1 cm) are noted, once adenomas are noted to have high-grade dysplasia (or villous histology), or once the patient turns 25.