Lower gastrointestinal bleeding causes

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]

Causes

Common causes

Common causes of lower gastrointestinal bleeding inclue:

• Colonic diverticulosis
  • Colonic diverticulosis is the most common cause of acute LGIB, accounting for 15% to 55% of all LGIB.
  • Hemorrhage results from rupture of the intramural branches (vasa recta) of the marginal artery at the dome of a diverticulum and can give rise to a massive, life-threatening LGIB.
  • Diverticulosis is the most common cause of bleeding in the elderly, as the prevalence of diverticular disease increases with age, being as high as 85% by the age of 85 years.

• Vascular ectasias (angiodysplasias/angioectasias):
  • Tortuous dilated submucosal vessels that account for approximately 10% of LGIB.
  • The prevalence of angiodysplasia is higher in older populations.
  • Angiodysplasia can also be found throughout the small bowel and is responsible for up to 40% of small intestinal bleeding in patients older than 40 years.
  • Angiodysplasia of the stomach and duodenum is responsible for up to 7% of UGIB.
• Iatrogenic:
  • Bleeding is recognized as the most common complication of colonoscopy and polypectomy, occurring in 0.3% to 6.1% of polypectomies.
  • Risk factors for bleeding include polyp size greater than 1 cm, patient age older than 65 years, presence of comorbid disease, and polypectomy using the cutting mode of current.
  • The risk is also greater in patients taking anticoagulant or antiplatelet agents.
• Ischemic colitis:
  • Ischemic colitis accounts for approximately 20% of LGIB
• Colorectal malignancy:
  • Colorectal cancer accounts for approximately 10% of bleeds, either as occult bleeding presenting with anemia or as frank blood loss per rectum
• Anorectal abnormalities:
  • Hemorrhoids, fissures, fistulae, and polyps can all present with bright red rectal bleeding, which may be intermittent in nature
  • Hemorrhoids are the most common cause of rectal bleeding in adults younger than 50 years
• Inflammatory bowel disease (IBD):
  • IBD refers to both Crohn disease and ulcerative colitis accounts for 5% to 10% of bleeds.
  • It is by far the most common cause of LGIB in Asian populations in whom the prevalence of diverticular disease is much lower.
• Infectious colitis:
  • The most common organisms in the U.S. are species of Salmonella, Campylobacter, Shigella, and Yersinia.

Less common causes

Less common causes of lower gastrointestinal bleeding include:

• Colonic polyps

• Radiation proctitis

• Rectal varices
• Stercoral ulceration

• Meckel diverticulum

• Intussusception
• Henoch-Schönlein purpura (HSP)