Lower gastrointestinal bleeding overview
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Differentiating Lower gastrointestinal bleeding from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Muhammad Saad, M.D.[2] Aditya Ganti M.B.B.S. [3]
Overview
Lower gastrointestinal bleeding (LGIB) is bleeding originating from a colorectal source distal to the ileocecal valve, typically presenting with hematochezia or bright red blood per rectum. The older definition based on bleeding distal to the ligament of Treitz has been superseded; bleeding between the ligament of Treitz and ileocecal valve is classified as small-bowel bleeding and follows a separate diagnostic and therapeutic pathway.[1] Stool appearance does not reliably determine anatomic source; brisk upper gastrointestinal bleeding can present with hematochezia, whereas slower LGIB may occasionally present with melena.[2]
Clinical burden
LGIB accounts for up to approximately 30% of gastrointestinal bleeding and causes more than 100,000 hospitalizations annually in the United States, with more than 270,000 emergency department visits and a hospitalization incidence of approximately 36 per 100,000 population, lower than that reported for upper gastrointestinal bleeding.[1][3][4] Patients are predominantly older adults with substantial comorbidity, and antiplatelet and anticoagulant use is common.[3] The burden has increased with population aging and expanding use of antithrombotic therapy.[3]
Clinical course and outcomes
Most episodes of LGIB are self-limited, and many patients do not require endoscopic, radiologic, or surgical hemostasis.[5] In-hospital mortality is generally low but varies across populations, with reported rates of approximately 3.4–8.8%.[1][6] Mortality is influenced substantially by comorbidity, hemodynamic instability, in-hospital onset of bleeding, and rebleeding. Patients who develop LGIB while already hospitalized have substantially higher mortality than those presenting from the community.[1][6]
Core clinical approach
Initial assessment and hemodynamic resuscitation should proceed simultaneously, with focused history, physical examination, digital rectal examination, and laboratory assessment.[1] The principal triage decision is based on hemodynamic stability and whether significant bleeding is ongoing.
- Hemodynamically stable patients → assess severity and risk, then perform colonoscopy after appropriate resuscitation and bowel preparation when indicated. Colonoscopy provides diagnostic evaluation and permits endoscopic therapy when a bleeding source is identified.[1][2]
- Hemodynamically significant or severe ongoing bleeding → promptly consider an upper GI source and obtain CT angiography (CTA) to localize active bleeding; a positive CTA can guide transcatheter arterial embolization.[1][7]
- In a hemodynamically stable patient with a high suspicion of active bleeding, CTA may also be considered as an initial diagnostic test when rapid localization of active bleeding is clinically important.[7]
- CTA is not useful once clinically significant bleeding has subsided, because the likelihood of demonstrating active extravasation falls substantially.[1][7]
Risk stratification
The Oakland score may supplement clinical judgment when identifying patients with LGIB who are at sufficiently low risk for adverse outcomes to permit early discharge and outpatient evaluation. An Oakland score of ≤8 identifies a low-risk group, but the score should not replace clinical assessment or consideration of ongoing bleeding, comorbidity, social circumstances, and follow-up reliability.[1] External validation studies support its ability to identify low-risk patients, although the evidence underlying threshold-based discharge remains limited.[1][3]
Assessment for an upper gastrointestinal source
Severe hematochezia should not automatically be attributed to a colorectal source. Clinical features favoring an upper GI source include hemodynamic instability, a history of peptic ulcer disease or decompensated liver disease, and a BUN-to-creatinine ratio >30; a BUN-to-creatinine ratio above this threshold has been associated with a substantially increased likelihood of upper GI bleeding.[1][2] The presence of blood clots in stool argues against an upper GI source.[1] Nasogastric aspirate has poor sensitivity for excluding an upper GI source and should not be relied upon as a definitive rule-out test.[1]
Clinically important principles
- Resuscitation and diagnostic assessment occur concurrently rather than sequentially in patients with significant bleeding.[1]
- The initial diagnostic pathway should be determined primarily by hemodynamic status and whether significant bleeding is ongoing.[1][7]
- CTA has high value when significant active bleeding is suspected but limited yield after bleeding has stopped.[1][7]
- In stable patients, colonoscopy remains an important diagnostic and therapeutic modality, but the optimal timing of colonoscopy remains unsettled.[1]
- Risk scores, including the Oakland score, should be treated as adjuncts to clinical judgment rather than absolute disposition rules.[1]
Common pitfalls
- Anchoring on a diagnosis of LGIB and missing a brisk upper GI source in a patient with severe hematochezia.
- Sending a hemodynamically unstable patient directly for bowel preparation and colonoscopy rather than prioritizing stabilization and appropriate localization of active bleeding.
- Obtaining CTA after clinically significant bleeding has ceased, when the likelihood of detecting active extravasation is low.
- Treating the Oakland score as a substitute for clinical judgment.
- Assuming that every patient with LGIB requires urgent endoscopic or radiologic hemostasis.
- Using nasogastric aspirate as a definitive test to exclude an upper GI source.
Scope of this overview
This Overview provides a high-level clinical framework. Detailed causes and epidemiology, diagnostic testing and performance characteristics, risk-stratification tools, colonoscopy, CT angiography, embolization, transfusion strategy, antithrombotic management, medical therapy, and surgical therapy should be addressed in their respective dedicated microchapters.
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 Sengupta N, Feuerstein JD, Jairath V; et al. (2023). "Management of Patients With Acute Lower Gastrointestinal Bleeding: An Updated ACG Guideline". The American Journal of Gastroenterology. 118 (2): 208–231. doi:10.14309/ajg.0000000000002130.
- ↑ 2.0 2.1 2.2 Gralnek IM, Neeman Z, Strate LL. (2017). "Acute Lower Gastrointestinal Bleeding". The New England Journal of Medicine. 376 (11): 1054–1063. doi:10.1056/NEJMcp1603455.
- ↑ 3.0 3.1 3.2 3.3 Alali AA, Almadi MA, Barkun AN. (2024). "Review article: Advances in the management of lower gastrointestinal bleeding". Alimentary Pharmacology & Therapeutics. 59 (5): 632–644. doi:10.1111/apt.17859.
- ↑ Ashley E. Aaron, Andrea Amabile, Ciro Andolfi, et al. Gastrointestinal Surgical Emergencies Textbook. American College of Surgeons. 2021.
- ↑ Karuppasamy K, Kapoor BS, Fidelman N; et al. (2021). "ACR Appropriateness Criteria® Radiologic Management of Lower Gastrointestinal Tract Bleeding: 2021 Update". Journal of the American College of Radiology. 18 (5S): S139–S152. doi:10.1016/j.jacr.2021.02.018.
- ↑ 6.0 6.1 Radaelli F, Frazzoni L, Repici A; et al. (2021). "Clinical Management and Patient Outcomes of Acute Lower Gastrointestinal Bleeding. A Multicenter, Prospective, Cohort Study". Digestive and Liver Disease. 53 (9): 1141–1147. doi:10.1016/j.dld.2021.01.002.
- ↑ 7.0 7.1 7.2 7.3 7.4 Sengupta N, Kastenberg DM, Bruining DH; et al. (2024). "The Role of Imaging for Gastrointestinal Bleeding: Consensus Recommendations From the American College of Gastroenterology and Society of Abdominal Radiology". The American Journal of Gastroenterology. 119 (3): 438–449. doi:10.14309/ajg.0000000000002631.