Upper gastrointestinal bleeding causes significant morbidity and mortality in the United States, and has been associated with increasing nonsteroidal anti-inflammatory drug use and the high prevalence of Helicobacter pylori infection in patients with peptic ulcer bleeding.
https://www.aafp.org/afp/2012/0301/p469.html
Diverticulosis: One of the most common causes of lower GI bleeding. Small out-pockets, or diverticula, form in the wall of the colon (large intestine), usually in a weakened area of the bowel wall.
https://www.emedicinehealth.com/gastrointestinal_bleeding/article_em.htm
In a review by Vernava and colleagues, patients with LGIB made up only 0.7% of all hospital admissions (17,941 patients); among the patients who underwent a diagnostic workup (4410 [24%]), the most common causes of bleeding were diverticular disease (60%), IBD (13%), and anorectal diseases (11%) (see Table 1 below).
https://emedicine.medscape.com/article/188478-overview
Angiodysplasia: Along with diverticulosis, this is one of the most common causes of lower GI bleeding. Angiodysplasia is a malformation of the blood vessels in the wall of the GI tract. These are most commonly in the large intestine and often bleed.
https://www.emedicinehealth.com/gastrointestinal_bleeding/article_em.htm
Lower gastrointestinal bleeding (LGIB) accounts for approximately 20-33% of episodes of gastrointestinal (GI) hemorrhage, with an annual incidence of about 20-27 cases per 100,000 population in Western countries. However, although LGIB is statistically less common than upper GI bleeding (UGIB), it has been suggested that LGIB is underreported...
https://emedicine.medscape.com/article/188478-overview
The diagram below provides an outline of the most common causes of LGIB, including anatomic (eg, diverticular bleeding), vascular (eg, angiodysplasia, ischemic colitis, radiation-induced colitis), neoplasms, and inflammatory.
https://emedicine.medscape.com/article/188478-overview
Gastrointestinal bleeding can be acute or serious. Both upper gastrointestinal bleeding and lower gastrointestinal bleeding have different causes, include ulcers, gastritis, cancer, infection, IBD, hemorrhoids, and anal fissures. Learn the signs, treatments, and risk factors of GI bleeding.
https://www.emedicinehealth.com/gastrointestinal_bleeding/article_em.htm
The causes of gastrointestinal (GI) bleeding are classified into upper or lower, depending on their location in the GI tract. Because GI bleeding is a symptom of many conditions, these conditions are all risk factors for getting a GI bleed.
https://www.emedicinehealth.com/gastrointestinal_bleeding/article_em.htm
The most common causes and risk factors for lower GI bleeding include. Diverticular disease (diverticulitis) gastrointestinal cancers, inflammatory bowel disease (IBD, Crohn's disease, ulcerative colitis), infectious diarrhea, angiodysplasia, polyps, hemorrhoids, and; anal fissures.
https://www.emedicinehealth.com/gastrointestinal_bleeding/article_em.htm
In a retrospective review of medical records from approximately 1100 patients with acute LGIB, all of whom were admitted to the surgical service of a single urban emergency hospital, Gayer et al determined that the most common etiologies for bleeding in these patients were diverticulosis (33.5%), hemorrhoids (22.5%), and carcinoma (12.7%).
https://emedicine.medscape.com/article/188478-overview
most common cause of acute gastrointestinal bleeding
Gastrointestinal bleeding have different causes, include ulcers, gastritis, cancer, infection, IBD, hemorrhoids, and anal fissures.