What is the approach to managing lower gastrointestinal (GI) bleeding in adults?

Management Approach to Lower GI Bleeding in Adults

The management of acute lower gastrointestinal bleeding requires a systematic approach beginning with risk stratification, followed by appropriate diagnostic evaluation and targeted interventions based on bleeding severity and hemodynamic stability. 1, 2

Initial Assessment and Risk Stratification

• Patients should be categorized into four groups: minor bleeding that resolves with conservative therapy, chronic intermittent bleeding, severe life-threatening bleeding with periods of stability, or continual active bleeding 1
• The Oakland score should be used to identify patients suitable for outpatient management (score ≤8) versus those requiring hospital admission (score >8) 1, 3
• Risk factors for severe lower GI bleeding include: initial heart rate >100/min, systolic blood pressure <115 mmHg, syncope, nontender abdominal examination, bleeding per rectum during first 4 hours of evaluation, aspirin use, and more than two active comorbid conditions 2
• The BLEED classification system (ongoing Bleeding, Low systolic blood pressure, Elevated prothrombin time, Erratic mental status, unstable comorbid Disease) can identify patients at high risk of adverse outcomes 2

Resuscitation and Blood Management

• Immediate resuscitation with intravenous fluids should be initiated for hemodynamically unstable patients 1, 3
• For hemodynamically stable patients with no cardiovascular disease, adopt a restrictive transfusion strategy with a hemoglobin threshold of ≤7 g/dL 3
• For patients with acute or chronic cardiovascular disease, use a more liberal transfusion strategy with a hemoglobin threshold of ≤8 g/dL and a post-transfusion target of ≥10 g/dL 3
• Correct coagulopathy or thrombocytopenia with fresh frozen plasma or platelets as needed 1

Diagnostic Approach

Rule Out Upper GI Source

• For patients with severe hematochezia and hypovolemia, consider an upper GI source, which accounts for 10-15% of such cases 2, 1
• Perform upper endoscopy early in patients with risk factors for peptic ulcer, portal hypertension, or angiodysplasia 2, 4

Colonoscopy

• Colonoscopy is the diagnostic procedure of choice for acute lower GI bleeding with a diagnostic accuracy of 72-86% 2, 1
• Perform colonoscopy during the hospital stay, though there is limited evidence that early colonoscopy (within 24 hours) significantly improves outcomes 3
• Rapid bowel cleansing prior to colonoscopy improves visualization and diagnostic yield 2, 1

Advanced Imaging

• For hemodynamically unstable patients with suspected ongoing bleeding, perform CT angiography before endoscopic or radiologic treatment to locate the bleeding site 3
• Radionuclide imaging with [99Tcm] pertechnetate-labeled red blood cell scanning can detect bleeding at rates of 0.1-0.5 mL/min and is useful for episodic bleeding 1
• A positive red blood cell scan should be followed by urgent angiography within 1 hour for potential therapeutic intervention 1

Therapeutic Interventions

Endoscopic Management

• Provide endoscopic hemostasis for high-risk stigmata including active bleeding, non-bleeding visible vessel, or adherent clot 5
• The choice of hemostasis technique (mechanical, thermal, injection, or combination) depends on bleeding etiology, access to the site, and endoscopist experience 5

Radiological Intervention

• Consider angiography with embolization for patients with ongoing bleeding not amenable to endoscopic therapy 2
• Intra-arterial vasopressin infusion can control bleeding in up to 91% of patients with diverticular disease or angiodysplasia, though bleeding recurs in up to 50% after cessation 2

Surgical Management

• Reserve surgery for patients with persistent hemodynamic instability despite resuscitation, transfusion requirements >6 units, or severe recurrent bleeding 2
• Accurate preoperative localization of the bleeding site is essential for successful segmental resection 2
• Blind segmental resection or emergency subtotal colectomy without localization are associated with high rebleeding rates (up to 33%) and mortality (33-57%) 2

Management of Antithrombotic Therapy

• For patients on vitamin K antagonists with major bleeding, withhold the medication and correct coagulopathy based on bleeding severity and thrombotic risk 3
• Temporarily withhold direct oral anticoagulants at presentation in patients with major lower GI bleeding 3
• Continue low-dose aspirin in patients taking it for secondary cardiovascular prevention; if withheld, resume preferably within 5 days of achieving hemostasis 3
• For patients on dual antiplatelet therapy, continue aspirin while the P2Y12 receptor antagonist can be temporarily interrupted based on bleeding severity and ischemic risk; restart within 5 days if still indicated 3

Common Pitfalls to Avoid

• Failing to consider an upper GI source in patients with severe hematochezia can lead to delayed diagnosis and treatment 1, 2
• Delaying colonoscopy may reduce the ability to identify stigmata of recent hemorrhage 1
• Performing blind segmental resection without adequate localization of the bleeding source leads to high rebleeding and mortality rates 2
• Permanently discontinuing antiplatelet therapy in patients with high cardiovascular risk can increase thromboembolic events 3