ABSTRACT
The causes of LGIB are multiple and varied. The most common etiologies include: diverticulosis, angiodysplasia (including arteriovenous malformations [AVMs], vascular ectasias, and angiomas), neoplasms, ischemic colitis, colitis, hemorrhoids and other anorectal diseases, postpolypectomy hemorrhage, and inflammatory bowel disease. In addition, in patients presenting with bright blood per rectum, as many as one-third are found to have bleeding localized to the small intestine and up to 11% are localized to the upper GI tract.(7) Longstreth’s recent review revealed that colonic diverticulosis was the leading cause of lower GI bleeding (41.6% of patients) which is consistent with other studies.(3, 8, 9) Of note, the other commonly quoted etiology, colonic angiodysplasia, accounted for only 6% of LGIBs.
