What is the treatment for a lower gastrointestinal (GI) bleed?

Treatment of Lower Gastrointestinal Bleeding

For lower GI bleeding, treatment begins with immediate hemodynamic resuscitation using crystalloid fluids, followed by colonoscopy within 24 hours as the primary diagnostic and therapeutic procedure, with endoscopic hemostasis for high-risk stigmata, and escalation to angiographic embolization or surgery only for persistent bleeding uncontrolled by endoscopy. 1, 2, 3

Initial Resuscitation and Stabilization

• Assess hemodynamic status immediately and initiate concurrent resuscitation with crystalloid fluids to restore end-organ perfusion in patients with hemodynamic instability 1, 2
• Transfuse blood when hemoglobin falls below 70-80 g/L, using a higher threshold (80 g/L) for patients with cardiovascular disease 1
• Correct coagulopathy with fresh frozen plasma and thrombocytopenia with platelets 1, 2
• Patients requiring ≥5 units of blood transfusion within 24 hours represent the highest-risk group for ongoing bleeding 4

Risk Stratification

• Use the Oakland score to identify low-risk patients (score ≤8) suitable for outpatient management versus high-risk patients (score >8) requiring hospital admission 2
• Categorize patients into four groups: minor bleeding resolving with conservative therapy, chronic intermittent bleeding, severe life-threatening bleeding with periods of stability, or continual active bleeding 1, 2
• Hemodynamic instability, particularly requiring ≥5 units transfusion, is the most powerful predictor of need for intervention (odds ratio 40) 4

Diagnostic Approach

Rule Out Upper GI Source First

• In patients with severe hematochezia and hemodynamic instability, perform upper endoscopy first, as 10-15% of these cases originate from an upper GI source 2, 5, 3
• Consider upper endoscopy early in patients with risk factors for peptic ulcer disease, portal hypertension, or angiodysplasia 2

Colonoscopy as Primary Diagnostic Tool

• Perform colonoscopy within 24 hours of presentation after rapid bowel preparation in hemodynamically stable patients 1, 3
• Colonoscopy has a diagnostic accuracy of 72-86% and serves as both diagnostic and therapeutic procedure 1, 2
• Urgent colonoscopy after rapid bowel cleansing is feasible and useful even in patients with severe hematochezia who are stabilized 2
• Obtain plain abdominal radiography before colonoscopy if bowel perforation or obstruction is suspected 2

Therapeutic Management

Endoscopic Hemostasis

• Provide endoscopic hemostasis therapy to patients with high-risk stigmata including active bleeding, non-bleeding visible vessel, or adherent clot 3
• Use mechanical, thermal, injection, or combination therapy based on bleeding etiology, access to the bleeding site, and endoscopist experience 3
• Combination endoscopic therapy is superior to single-modality treatment 1
• Consider repeat colonoscopy with endoscopic hemostasis for patients with evidence of recurrent bleeding 3

Angiographic Intervention

• For active bleeding not controlled by endoscopic means, proceed to angiography with superselective embolization, especially after a positive bleeding scan 1, 5, 6
• In hemodynamically unstable patients with ongoing bleeding who cannot tolerate bowel preparation, consider urgent angiography without colonoscopy 2, 3
• Multidetector CT angiography has an accuracy rate of 54-79% and can help localize bleeding before formal angiography 2
• Radionuclide imaging with [99Tcm] pertechnetate-labeled red blood cell scanning detects bleeding at rates of 0.1-0.5 mL/min and should be followed by urgent angiography within 1 hour if positive 2

Surgical Intervention

• Surgery is reserved for persistent bleeding after failed endoscopic and angiographic interventions 5, 3
• The bleeding source must be carefully localized by colonoscopy or angiography before surgical resection 3
• Surgical decisions should be individualized based on severity of bleeding, adequacy of hemostasis attempts, and patient comorbidities 3

Management Algorithm

1. Assess hemodynamic status and initiate crystalloid resuscitation; transfuse if hemoglobin <70-80 g/L 1, 2
2. Calculate Oakland score for risk stratification 2
3. If severe hematochezia with hemodynamic instability, perform upper endoscopy first to exclude upper GI source 2, 5
4. For hemodynamically stable patients, perform colonoscopy within 24 hours after rapid bowel preparation 1, 3
5. Provide endoscopic hemostasis for high-risk stigmata (active bleeding, visible vessel, adherent clot) 3
6. If bleeding persists or recurs, consider repeat colonoscopy or proceed to angiography with embolization 1, 5, 6
7. Reserve surgery for persistent bleeding after failed endoscopic and angiographic interventions 5, 3

Critical Pitfalls to Avoid

• Failing to consider an upper GI source in severe hematochezia with hemodynamic instability leads to delayed diagnosis and treatment 2
• Delayed colonoscopy reduces diagnostic yield, particularly for identifying stigmata of recent hemorrhage 2
• Overreliance on radionuclide imaging without confirmatory colonoscopy or angiography before surgery can lead to incorrect localization 2
• Most patients (86%) with GI bleeding of unknown source stop bleeding spontaneously, so avoid overly aggressive intervention in stable patients 7

Special Considerations

• Patients on anticoagulants or antiplatelet agents have more severe bleeding (55.1% vs 35.4%), longer hospital stays, higher transfusion requirements, and more complications 8
• Nonsteroidal anti-inflammatory drugs should be avoided in patients with history of lower GI bleeding, particularly from diverticulosis or angioectasia 3
• Patients with established high-risk cardiovascular disease should not stop aspirin therapy (secondary prophylaxis) during lower GI bleeding; timing of resumption depends on bleeding severity and thromboembolic risk 3
• Diverticulosis remains the most common source of lower GI bleeding across all patient groups 8