Most Common Causes of GI Bleeding
The most common cause of upper gastrointestinal bleeding (UGIB) is peptic ulcer disease (specifically duodenal ulcers, followed by gastric ulcers and gastric erosions), while the most common cause of lower gastrointestinal bleeding (LGIB) is diverticulosis. 1, 2
Upper Gastrointestinal Bleeding (UGIB)
According to the American Society for Gastrointestinal Endoscopy survey, the most common etiologies of UGIB in order of frequency are 1:
- Duodenal ulcer (most common)
- Gastric erosions
- Gastric ulcer
- Varices
- Mallory-Weiss tears
- Esophagitis
- Duodenitis
- Neoplasm
Peptic ulcer disease accounts for 30-50% of all UGIB cases 3, making ulcer disease the dominant etiology. However, recent data shows a 30% decrease in hospitalizations for peptic ulcer bleeding, while bleeding from malignancy, Dieulafoy's lesions, and angiodysplasia has increased by 50%, 33%, and 32% respectively 3.
Important Clinical Context
- UGIB occurs proximal to the ligament of Treitz (esophagus, stomach, or duodenum) 1
- Mortality rates remain as high as 14% despite declining incidence 1
- Ulcer disease is commonly associated with H. pylori infection or NSAID/aspirin use 4
- Population variations exist: inner-city populations show relatively higher proportions of variceal hemorrhage and erosive gastritis 1
Lower Gastrointestinal Bleeding (LGIB)
The most common causes of LGIB are 2:
- Diverticulosis (most common, accounting for 21-41% of cases)
- Angiodysplasia (2-40% depending on population studied)
- Hemorrhoids and anorectal disease
- Ischemic colitis
- Cancer/polyps
- Colitis (inflammatory bowel disease, infectious, radiation)
Geographic and Population Variations
There are notable geographic differences in LGIB etiology 5:
- Western populations: Diverticular bleeding is the leading cause
- Indian studies: Colitis and hemorrhoids are the leading causes
Key Clinical Pearls
- LGIB is defined as bleeding from the colon or anorectum (distal to ligament of Treitz) 5
- Incidence increases dramatically with age (>200-fold increase from age 20-80 years) 2, explained by increasing prevalence of diverticulosis and angiodysplasia
- 10-15% of patients presenting with acute severe hematochezia actually have an upper GI source 2, 6
- Mortality rate is 2-4%, significantly lower than UGIB 2
- 80-85% of LGIB cases stop spontaneously 2
Common Pitfall to Avoid
Do not assume bright red blood per rectum always indicates LGIB—brisk UGIB can present with hematochezia rather than melena. Consider upper endoscopy if no source is identified on initial evaluation, especially in hemodynamically unstable patients with risk factors for UGIB (peptic ulcer history, antiplatelet use, elevated BUN/creatinine ratio) 6.