What are common causes of lower GI bleeding (LGIB)?

Updated: Jul 26, 2019
  • Author: Burt Cagir, MD, FACS; Chief Editor: BS Anand, MD  more...
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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%). [14] The investigators also found that most patients in the study (55.5%) presented with hematochezia, with the next most frequent presentations being maroon stools (16.7%) and melena (11%).

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). [13] These figures differ somewhat from the study by Gayer et al. Although some publications have reported arteriovenous malformations (AVMs) as a common cause of LGIB, Vernava et al reported the true incidence of these lesions at 3%. [15]

Table 1. Common Causes of Lower Gastrointestinal Bleeding in Adults (Open Table in a new window)

Lower Gastrointestinal Bleeding in Adults

Patients (%)

Diverticular disease

  • Diverticulosis/diverticulitis of small intestine

  • Diverticulosis/diverticulitis of colon


Inflammatory bowel disease

  • Crohn disease of small bowel, colon, or both

  • Ulcerative colitis

  • Noninfectious gastroenteritis and colitis


Benign anorectal diseases

  • Hemorrhoids

  • Anal fissure

  • Fistula-in-ano



  • Malignant neoplasia of small intestine

  • Malignant neoplasia of colon, rectum, and anus




Arteriovenous malformations (AVMs)




Source: Vernava AM, Longo WE, Virgo KS. A nationwide study of the incidence and etiology of lower gastrointestinal bleeding. Surg Res Commun. 1996;18:113-20. [13]

Longstreth reviewed the discharge summary and colonoscopy data from a large health maintenance organization with members in the San Diego, California, area; of 235 hospital admissions for 219 patients, the estimated hospital admission rate for LGIB was found to be 20 patients per 100,000 admissions, with bleeding from diverticular disease the most common reason (42%), followed by colorectal malignancies (9%) and ischemic colitis (8.7%). [16] The incidence of LGIB due to colonic angiodysplasias was 6%. These findings were consistent with those of the Veterans Administration database study by Vernava et al, although that study was limited to males.

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