What is the best approach to managing a lower gastrointestinal (GI) bleed?

Management of Lower Gastrointestinal Bleeding

The best approach to managing lower gastrointestinal (GI) bleeding begins with immediate assessment of hemodynamic stability, followed by colonoscopy within 24 hours after adequate bowel preparation as the first-line diagnostic and therapeutic intervention. 1, 2

Initial Assessment and Stabilization

1. Hemodynamic Assessment and Resuscitation:

   • Evaluate vital signs for signs of shock (tachycardia, hypotension)
   • Establish IV access and begin fluid resuscitation if needed
   • Consider blood transfusion for hemoglobin <70 g/L or patients with ongoing bleeding

2. Risk Stratification:

   • Use the Oakland score to determine severity:
     • Score ≤8: Minor bleed
     • Score >8: Major bleed
   • Consider factors: age, gender, previous LGIB admission, DRE findings, heart rate, systolic BP, and hemoglobin 1

3. Digital Rectal Examination:

   • Essential to confirm presence of blood and assess color/characteristics

Diagnostic Approach

1. Colonoscopy:

   • Perform within 24 hours after adequate bowel preparation 1, 2
   • Allows direct visualization, biopsy, and therapeutic intervention
   • Most effective when performed early (within 24 hours) to identify bleeding source and provide endoscopic treatment 3

2. For Hemodynamically Unstable Patients with Hematochezia:

   • Consider upper endoscopy first to rule out upper GI source 2
   • Up to 15% of apparent lower GI bleeding may be from upper GI sources

3. If Colonoscopy is Negative or Not Feasible:

   • CT angiography for patients with ongoing bleeding (can detect bleeding at rates of 0.3-1.0 mL/min) 1
   • Nuclear scintigraphy (tagged RBC scan) for intermittent bleeding
   • Angiography for patients with severe ongoing bleeding 4

4. Small Bowel Evaluation (if colonoscopy and upper endoscopy negative):

   • Video capsule endoscopy (identifies bleeding source in 55-65% of cases) 4
   • Push enteroscopy for proximal small bowel examination
   • Consider Meckel's scan in young patients with unexplained bleeding 4

Therapeutic Interventions

1. Endoscopic Hemostasis:

   • Indicated for high-risk stigmata: active bleeding, visible vessel, or adherent clot 1, 2
   • Methods include:
     • Mechanical (clips)
     • Thermal coagulation
     • Injection therapy
     • Combination therapy

2. Radiological Interventions:

   • Angiographic embolization for patients with ongoing bleeding not amenable to endoscopic treatment
   • Intra-arterial vasopressin infusion can control bleeding in up to 91% of cases with diverticular disease or angiodysplasia 4
   • Note: Bleeding recurs in up to 50% after vasopressin cessation 4

3. Surgical Management:

   • Reserved for cases where other interventions fail
   • Indications include:
     • Persistent hemodynamic instability despite resuscitation
     • Transfusion requirement >6 units
     • Recurrent severe bleeding 4, 1
   • Surgical intervention is necessary in only 18-25% of patients requiring blood transfusion 4

Management of Medications

1. Antiplatelet/Anticoagulant Management:
   • Discontinue NSAIDs in patients with history of LGIB
   • Do not stop aspirin for secondary cardiovascular prophylaxis 2
   • Warfarin should be interrupted and reversed with prothrombin complex and vitamin K in unstable bleeding 1

Common Causes and Follow-up

1. Most Common Causes:

   • Diverticular bleeding (26.4%)
   • Benign anorectal conditions (16.7%)
   • Angiodysplasia
   • Ischemic colitis 1, 5

2. Follow-up Care:

   • Provide iron supplementation for patients with anemia
   • Consider age-appropriate cancer screening (colorectal cancer found in 6% of patients with rectal bleeding) 1
   • Monitor for rebleeding (occurs in 13.6% during admission and 4.4% within 28 days post-discharge) 5

Prognosis

• In-hospital mortality is 3.4%, increasing to 18% for inpatients who develop bleeding during hospitalization 1, 5
• Mortality is generally related to comorbidities rather than exsanguinating hemorrhage 5
• Rebleeding is associated with higher mortality (7.1%) 5

Pitfalls to Avoid

• Delaying colonoscopy beyond 24 hours reduces diagnostic yield
• Failing to consider upper GI source in patients with hematochezia and hemodynamic instability
• Overlooking medication effects (NSAIDs, antiplatelets, anticoagulants)
• Neglecting to perform adequate bowel preparation before colonoscopy
• Premature discontinuation of aspirin in patients with established cardiovascular disease