Acute lower gastrointestinal (GI) bleeding includes a wide clinical spectrum, ranging from minute bleeding to massive haemorrhage with haemodynamic instability. Lower GI bleeding is approximately one fifth as common as upper GI bleeding and accounts for approximately 20 to 33 hospitalisations per 100,000 adults per year.[1]Longstreth GF. Epidemiology and outcome of patients hospitalized with acute lower gastrointestinal hemorrhage: a population-based study. Am J Gastroenterol. 1997 Mar;92(3):419-24.
http://www.ncbi.nlm.nih.gov/pubmed/9068461?tool=bestpractice.com
[2]Lanas A, García-Rodríguez LA, Polo-Tomás M, et al. Time trends and impact of upper and lower gastrointestinal bleeding and perforation in clinical practice. Am J Gastroenterol. 2009 Jul;104(7):1633-41.
http://www.ncbi.nlm.nih.gov/pubmed/19574968?tool=bestpractice.com
The incidence of lower GI bleeding increases with age.
In developed countries, common causes of acute lower GI bleeding resulting in significant blood loss include colonic diverticular disease and angiodysplasia. Patients with severe bleeding or significant comorbid states require rapid identification and aggressive resuscitation. Haemodynamically insignificant bleeding may frequently result from haemorrhoids and colonic neoplasms. Rare causes of bleeding include solitary rectal ulcer, vasculitis, and endometriosis. Fifteen percent (15%) of patients who present with lower GI bleeding have an upper GI source following investigation.[3]Sengupta N, Feuerstein JD, Jairath V, et al. Management of patients with acute lower gastrointestinal bleeding: an updated ACG guideline. Am J Gastroenterol. 2023 Feb 1;118(2):208-31.
https://www.doi.org/10.14309/ajg.0000000000002130
http://www.ncbi.nlm.nih.gov/pubmed/36735555?tool=bestpractice.com
[4]Laine L, Shah A. Randomized trial of urgent vs. elective colonoscopy in patients hospitalized with lower GI bleeding. Am J Gastroenterol. 2010 Dec;105(12):2636-41; quiz 2642.
https://www.doi.org/10.1038/ajg.2010.277
http://www.ncbi.nlm.nih.gov/pubmed/20648004?tool=bestpractice.com
The source of lower GI bleeding cannot be definitively identified in up to 25% of patients.[5]Rockey DC. Lower gastrointestinal bleeding. Gastroenterology. 2006 Jan;130(1):165-71.
https://www.gastrojournal.org/article/S0016-5085(05)02404-2/fulltext?referrer=https%3A%2F%2Fpubmed.ncbi.nlm.nih.gov%2F
http://www.ncbi.nlm.nih.gov/pubmed/16401479?tool=bestpractice.com
[6]Schmulewitz N, Fisher DA, Rockey DC. Early colonoscopy for acute lower GI bleeding predicts shorter hospital stay: a retrospective study of experience in a single center. Gastrointest Endosc. 2003 Dec;58(6):841-6.
http://www.ncbi.nlm.nih.gov/pubmed/14652550?tool=bestpractice.com
Colonoscopy is the mainstay of the evaluation in patients in whom anorectal or upper GI causes have been ruled out. This is performed to localise the bleeding source and to enable haemostasis. Endoscopic haemostasis is successful in most cases.
Modalities including computed tomography (CT) angiography, catheter angiography, and radionuclide imaging may have a role in specific clinical scenarios.