Pathway AI

Account ⋅ Sign Out

Table of contents

Lower gastrointestinal bleeding

LGIB is defined as gastrointestinal bleeding originating distal to the ileocecal valve, which includes the colon, rectum and anus.
Notable causes of LGIB include diverticulosis (42.5%), ischemic colitis (12.5%), hemorrhoids (12.5%), colorectal polyps or neoplasms (8.5%), angioectasias (7.5%), postpolypectomy bleeding (4.5%), IBD (4%), infectious colitis (3.5%), stercoral ulceration (< 2.5%), colorectal varices (< 1.5%), radiation proctopathy (< 1%), NSAID-inducted colopathy (< 1%), and Dieulafoy's lesions (< 1%).
In the US, the age- and sex-adjusted incidence of hospitalization for LGIB is estimated at 35.7 cases per 100,000 person-years.
Disease course
LGIB classically manifests as hematochezia (maroon or red blood passed through the rectum). Uncommonly, bleeding from the right colon may present with melena. If bleeding is severe, manifestations of hemorrhagic shock may be present.
Prognosis and risk of recurrence
LGIB is associated with an estimated bleeding-related mortality of 1.1% (95% CI, 0.6-1.8%), and an overall rebleeding rate of 13.5% (95% CI, 11.8-15.5%).
Key sources
The following summarized guidelines for the evaluation and management of lower gastrointestinal bleeding are prepared by our editorial team based on guidelines from the American College of Gastroenterology (ACG 2023; 2016), the European Society of Gastrointestinal Endoscopy (ESGE 2023), the American College of Gastroenterology (ACG/CAG 2022), the British Society for Haematology (BSH 2022), the European Society of Intensive Care Medicine (ESICM 2021), the British Society of Gastroenterology (BSG 2019), and the American Society for Gastrointestinal Endoscopy (ASGE 2017; 2014).


1.Classification and risk stratification

Risk stratification: as per ACG 2023 guidelines, consider using risk stratification tools (such as the Oakland score ≤ 8) to identify low-risk patients with LGIB being appropriate for early discharge and outpatient diagnostic evaluation. Use risk scores to supplement but not replace clinician judgment.
Create free account

2.Diagnostic investigations

Clinical assessment: as per ACG 2016 guidelines, elicit a focused history, perform a physical examination, and obtain laboratory evaluation at the time of patient presentation to assess the severity of bleeding and its possible location and etiology. Obtain initial patient assessment and perform hemodynamic resuscitation simultaneously.

More topics in this section

  • CTA

  • CT or MR enterography

  • RBC scan

3.Diagnostic procedures

Bowel preparation: perform rapid bowel purge following hemodynamic resuscitation in patients with high-risk clinical features and signs or symptoms of ongoing bleeding, and perform colonoscopy within 24 hours of patient presentation.
Show 3 more

More topics in this section

  • Lower gastrointestinal endoscopy

  • Upper gastrointestinal endoscopy

  • Video capsule endoscopy

  • Small bowel endoscopy

4.Medical management

Setting of care
Admit patients with major LGIB to the hospital for colonoscopy on the next available list.
Consider discharging patients presenting with minor self-terminating bleeding (such as those with an Oakland score ≤ 8 points), in the absence of other indications for hospital admission, for urgent outpatient investigation.

More topics in this section

  • Intravenous fluids

  • Management of anticoagulant and antiplatelet therapy (general principles)

  • Management of anticoagulant and antiplatelet therapy (warfarin)

  • Management of anticoagulant and antiplatelet therapy (DOACs)

  • Management of anticoagulant and antiplatelet therapy (antiplatelets)

  • Tranexamic acid

  • Iron therapy

5.Therapeutic procedures

Red blood cell transfusion: as per ACG 2023 guidelines, consider using a restrictive strategy of RBC transfusion (threshold for transfusion at a hemoglobin level of 7 g/dL) in hemodynamically stable patients with LGIB.

More topics in this section

  • Platelet and plasma transfusion

  • Endoscopic hemostasis (general principles)

  • Endoscopic hemostasis (diverticular bleeding)

  • Endoscopic hemostasis (angioectasia bleeding)

  • Endoscopic hemostasis (post-polypectomy bleeding)

  • Angioembolization

6.Surgical interventions

Indication for surgery: as per BSG 2019 guidelines, do not perform emergency laparotomy unless every effort has been made to localize bleeding by radiological and/or endoscopic modalities, except under exceptional circumstances.

7.Preventative measures

Secondary prevention: avoid using non-aspirin NSAIDs in patients with a history of acute LGIB, particularly if secondary to diverticulosis or angioectasia.

8.Follow-up and surveillance

Indications for specialist consultation: obtain surgical and radiologic consultation in patients with severe hematochezia unable to be stabilized for endoscopy or if endoscopic evaluation failed to reveal a bleeding source.

More topics in this section

  • Management of recurrent bleeding

9.Quality improvement

Hospital standards: ensure that all hospitals have a gastrointestinal bleeding lead and agreed pathways for the management of acute LGIB.
Show 2 more