What is the management approach for a patient presenting with a lower gastrointestinal (GI) bleed?

Management of Lower Gastrointestinal Bleeding

Initial Assessment and Hemodynamic Stabilization

All patients presenting with lower GI bleeding should have immediate hemodynamic assessment using shock index (heart rate ÷ systolic blood pressure), with a shock index >1 defining instability and mandating urgent CT angiography rather than colonoscopy. 1

• Place at least two large-bore IV catheters immediately for rapid volume expansion 2
• Initiate crystalloid resuscitation to restore hemodynamic stability 2
• Perform digital rectal examination to confirm blood in stool and exclude anorectal pathology 1
• Check for orthostatic hypotension, which indicates significant blood loss requiring ICU admission 1
• Always consider an upper GI source in hemodynamically unstable patients, even with hematochezia, as failure to do so leads to delayed diagnosis 1, 2, 3

Risk Stratification for Hemodynamically Stable Patients

For stable patients (shock index ≤1), calculate the Oakland score incorporating age, gender, previous LGIB admission, digital rectal examination findings, heart rate, systolic blood pressure, and hemoglobin level. 1

• Oakland score ≤8 points: Safe for discharge with urgent outpatient investigation 1, 4
• Oakland score >8 points: Requires hospital admission for colonoscopy 1, 4

Transfusion Strategy

Use restrictive transfusion thresholds for clinically stable patients without cardiovascular disease: hemoglobin trigger 70 g/L with target 70-90 g/L. 1, 4

• For patients with cardiovascular disease, use hemoglobin trigger 80 g/L with target ≥100 g/L 1, 4
• This restrictive approach prioritizes mortality reduction over liberal transfusion strategies 1

Management Algorithm Based on Hemodynamic Status

Hemodynamically Unstable Patients (Shock Index >1)

Proceed immediately to CT angiography (CTA) as the first diagnostic step—this provides the fastest, least invasive means to localize bleeding before any therapeutic intervention. 1, 2

• Do NOT perform colonoscopy in unstable patients, as guidelines explicitly recommend against this approach 1
• Following positive CTA, perform catheter angiography with embolization within 60 minutes in centers with 24/7 interventional radiology 1, 2
• If no lower GI source identified on CTA, perform upper endoscopy to exclude upper GI bleeding 1
• Surgery is reserved only for patients who fail angiographic intervention or continue deteriorating despite all localization attempts 1
• If patient remains unstable despite aggressive resuscitation, proceed directly to surgery 1

Hemodynamically Stable Patients

Perform colonoscopy within 24 hours after adequate bowel preparation as the initial diagnostic and therapeutic procedure. 4, 5

• Colonoscopy allows both diagnosis and endoscopic hemostasis for high-risk stigmata (active bleeding, non-bleeding visible vessel, adherent clot) 5
• Endoscopic hemostasis modalities include mechanical, thermal, injection, or combination therapy based on bleeding etiology and site accessibility 5

Coagulopathy Management

Warfarin

Interrupt warfarin immediately at presentation and reverse anticoagulation with prothrombin complex concentrate (PCC) and vitamin K for unstable GI hemorrhage. 1, 2

• If PCC unavailable, use fresh frozen plasma 4
• For patients with low thrombotic risk, restart warfarin 7 days after hemorrhage 1, 2
• Correct INR >1.5 with fresh frozen plasma 1

Direct Oral Anticoagulants (DOACs)

Temporarily withhold DOACs at presentation in patients with major lower GI bleeding. 4

Platelets

Transfuse platelets if count <50,000/µL. 1

Antiplatelet Management

For aspirin used in secondary cardiovascular prevention, do NOT routinely stop; if stopped, restart as soon as hemostasis is achieved. 1, 4

• Aspirin for primary prophylaxis should be permanently discontinued 1
• For dual antiplatelet therapy (aspirin + P2Y12 inhibitor), continue aspirin; the P2Y12 inhibitor can be continued or temporarily interrupted based on bleeding severity and ischemic risk 4
• If P2Y12 inhibitor interrupted, restart within 5 days if still indicated 4

ICU Admission Criteria

Admit to ICU if any of the following are present: 1

• Orthostatic hypotension
• Hematocrit decrease ≥6%
• Transfusion requirement >2 units packed red blood cells
• Continuous active bleeding
• Persistent hemodynamic instability despite aggressive resuscitation

Critical Pitfalls to Avoid

• Never perform colonoscopy as initial approach in unstable patients (shock index >1), as this delays definitive localization and treatment 1
• Failing to consider upper GI source in hemodynamically unstable patients is a common error leading to delayed diagnosis 1, 2, 3
• Mortality in lower GI bleeding relates primarily to comorbidity rather than exsanguination, with overall in-hospital mortality 3.4% but rising to 20% in patients requiring ≥4 units of red cells 1
• Avoid diagnostic laparotomy unless every effort at radiological and endoscopic localization has failed 1