Gastrointestinal Bleeding Causes and Incidence

Upper GI Bleeding Sources

The American College of Radiology notes that peptic ulcer disease accounts for the majority of nonvariceal upper GI bleeding, with gastric ulcers representing 32% and duodenal ulcers 28% of cases in large prospective series, primarily related to Helicobacter pylori infection and NSAID use 2
Esophageal varices represent 9% of upper GI bleeding cases, occurring predominantly in patients with cirrhosis and portal hypertension, although this fact is from a less preferred source 3, a better source indicates that hemobilia and aortoenteric fistula are rare but potentially catastrophic causes 2

The American Gastroenterological Association implies that diverticulosis is the leading cause of lower GI bleeding, accounting for 30-41% of cases across multiple studies, with prevalence increasing significantly with age 1
Colitis and ulcers, including inflammatory bowel disease, infectious colitis, radiation colitis, and ischemic colitis, represent 12-21% of cases 1
Anorectal sources, such as hemorrhoids, anal fissures, and rectal ulcers, account for 5-14% of cases 1
Cancer and polyps represent 6-14% of lower GI bleeding, with higher percentages in some series 1
Angiodysplasia accounts for 3-40% of cases, with significant variation across studies, and like diverticulosis, increases in prevalence with age 1

Approximately 10-15% of patients presenting with acute severe hematochezia actually have an upper GI source identified on upper endoscopy, emphasizing the importance of considering upper sources even with bright red blood per rectum 1
Upper GI bleeding has an incidence of 61-78 cases per 100,000 persons, which is 4-5 times higher than lower GI bleeding (20.5-27 cases per 100,000) 2
Mortality rates are 2-10% for upper GI bleeding and 2-4% for lower GI bleeding, though 75-85% of cases stop spontaneously 1