Management of Lower Gastrointestinal Bleeding (LGIB)
Risk Stratification and Disposition
Use the Oakland score immediately to determine whether the patient requires hospital admission or can be safely discharged for outpatient investigation. 1
Oakland Score Components:
- Age: <40 (0 points), 40-69 (1 point), ≥70 (2 points) 1
- Gender: Female (0 points), Male (1 point) 1
- Previous LGIB admission: No (0), Yes (1) 1
- Digital rectal exam findings: No blood (0), Blood (1) 1
- Heart rate: <70 (0), 70-89 (1), 90-109 (2), ≥110 (3) 1
- Systolic BP: <90 (5), 90-119 (4), 120-129 (3), 130-159 (2), ≥160 (0) 1
- Hemoglobin (g/L): <70 (22), 70-89 (17), 90-109 (13), 110-129 (8), 130-159 (4), ≥160 (0) 1
Patients scoring ≤8 points with no other indications for admission can be discharged immediately from the emergency department for urgent outpatient colonoscopy within 2 weeks, particularly if age >50 given the 6% risk of underlying bowel cancer. 1
Patients scoring >8 points require hospital admission for inpatient management. 1
Hemodynamically Unstable Patients (Shock Index >1)
Calculate the shock index (heart rate ÷ systolic blood pressure) immediately—a value >1 defines hemodynamic instability and mandates CT angiography as the first-line investigation, NOT colonoscopy. 1, 2, 3
Diagnostic Approach for Unstable Patients:
Perform CT angiography immediately to localize the bleeding source before any therapeutic intervention. 1, 2 CTA has sensitivity of 79-95% and specificity of 95-100% for detecting bleeding when velocity is 0.3-1.0 mL/min. 1, 3
CTA is preferred over colonoscopy in unstable patients because it can identify upper GI tract or small bowel sources, requires no bowel preparation, and is rapidly accessible. 1
Always consider an upper GI source in hemodynamically unstable patients, even with bright red rectal bleeding—perform upper endoscopy immediately if CTA identifies no source. 1, 2
Management After Positive CTA:
Proceed to catheter angiography with embolization within 60 minutes if interventional radiology is available 24/7. 2
If the patient remains in hemorrhagic shock despite resuscitation (non-responder), proceed directly to emergency surgery. 2
Hemodynamically Stable Patients (Major Bleed, Oakland Score >8)
Admit patients with major bleeding (Oakland score >8) to hospital for colonoscopy on the next available list after adequate bowel preparation. 1
Colonoscopy Timing and Preparation:
Colonoscopy should be performed within 24 hours after adequate bowel preparation with polyethylene glycol. 1, 4 There is no high-quality evidence that urgent colonoscopy (<12 hours) improves outcomes compared to elective colonoscopy (36-60 hours). 1
Bowel preparation with polyethylene glycol improves diagnostic yield and reduces need for repeat colonoscopy. 1 The most common complications are hypotension and vomiting, though aspiration pneumonia is rare. 1
Anorectal Assessment:
- Perform direct anorectal inspection in all patients using rigid sigmoidoscopy, proctoscopy, or flexible endoscopy with retroflexion, as anorectal conditions account for 16.7% of diagnoses. 1
Resuscitation and Transfusion Strategy
Place two large-bore intravenous catheters and initiate crystalloid resuscitation immediately. 2, 3
Red Blood Cell Transfusion Thresholds:
For patients without cardiovascular disease: transfuse at hemoglobin <7 g/dL with target range 7-9 g/dL (restrictive strategy). 2, 4
For patients with cardiovascular disease: transfuse at hemoglobin <8 g/dL with target ≥10 g/dL (liberal strategy). 2, 4
Anticoagulation Management
For patients on warfarin with unstable LGIB, interrupt warfarin immediately and reverse anticoagulation with four-factor prothrombin complex concentrate plus intravenous vitamin K. 2, 4
For patients on direct oral anticoagulants (DOACs), temporarily withhold the medication at presentation. 4
For patients on aspirin for secondary cardiovascular prevention, do NOT discontinue aspirin—the cardiovascular risks outweigh GI bleeding risks. 3, 4 If withheld, restart within 5-7 days. 2, 3
For patients on dual antiplatelet therapy (aspirin + P2Y12 inhibitor), continue aspirin but consider temporarily interrupting the P2Y12 inhibitor based on bleeding severity and ischemic risk; restart within 5 days if interrupted. 4
Common Pitfalls to Avoid
Never perform colonoscopy first in hemodynamically unstable patients (shock index >1)—always obtain CTA first to localize bleeding and exclude upper GI or small bowel sources. 1, 2
Never assume bright red rectal bleeding with hemodynamic instability is from a lower GI source—up to 10-15% originate proximal to the ligament of Treitz. 1, 5
Never use urgent colonoscopy (<12 hours) routinely—there is no evidence it improves diagnostic yield, therapeutic success, length of stay, or transfusion requirements compared to colonoscopy within 24 hours. 1
Never discharge patients with Oakland score >8 for outpatient management—they require hospital admission. 1
Never stop aspirin in patients taking it for secondary cardiovascular prevention unless bleeding is life-threatening. 3, 4