What are the evaluation and treatment options for hematochezia (passage of blood in stool)?

Evaluation and Management of Hematochezia

For patients presenting with blood in stool (hematochezia), immediate hemodynamic assessment is critical, followed by upper and lower endoscopy in stable patients, with colonoscopy being the preferred initial diagnostic approach over flexible sigmoidoscopy to avoid missing proximal lesions and reduce overall costs. 1

Initial Assessment and Resuscitation

Hemodynamic Stabilization

• Assess vital signs immediately to determine if the patient is hemodynamically unstable (hypotension, tachycardia, signs of shock) 1
• For unstable patients with hemorrhagic shock non-responsive to resuscitation, proceed directly to emergency surgery without delay for diagnostic procedures 1
• For stable or stabilized patients, initiate IV fluid resuscitation with goal of maintaining mean arterial pressure >65 mmHg 1
• Transfuse packed red blood cells to maintain hemoglobin >7 g/dL in most patients 1
• Target hemoglobin >9 g/dL for patients with massive bleeding, significant cardiovascular disease, or anticipated delays in intervention 1
• Correct coagulopathy before endoscopic procedures 1

Risk Stratification by History

Key historical features that predict substantial pathology include:

• Blood mixed within stool (not just on surface or toilet paper) 2
• Frequent bleeding episodes (multiple times per month) 2
• Short duration of symptoms before seeking care 2
• Age >50 years increases risk of colorectal cancer 3

Important caveat: Clinical assessment alone cannot reliably distinguish patients with significant colonic lesions from those without, so endoscopic evaluation remains essential 2

Diagnostic Approach

Endoscopic Evaluation

For hemodynamically stable patients:

1. Perform upper endoscopy (EGD) first to exclude upper GI bleeding sources, as up to 15% of patients with apparent hematochezia have upper GI sources 1

2. Proceed with colonoscopy as the primary lower GI diagnostic tool rather than flexible sigmoidoscopy 1

   • Colonoscopy should be performed within 24 hours for patients with high-risk features or ongoing bleeding 1
   • Bright red blood does NOT reliably indicate distal bleeding: 9% of patients with bright red hematochezia have proximal lesions including cancer 4
   • Flexible sigmoidoscopy misses approximately 5% of substantial lesions and requires subsequent colonoscopy for surveillance anyway 2
   • Colonoscopy is more cost-effective as initial approach, saving $12-116 per patient compared to sigmoidoscopy-first strategy 4

3. For patients with severe ongoing bleeding, urgent colonoscopy after oral purge (preferably sulfate-based rather than saline) is safe and effective 5

   • Allows both diagnosis (effective in 94% of cases) and therapeutic intervention 5
   • Can be performed safely in ICU setting 5

Advanced Imaging

For patients with ongoing bleeding who are hemodynamically stable after resuscitation:

• CT angiography should be performed as it detects bleeding at rates as low as 0.3 mL/min 1
• CT before colonoscopy increases detection rate of vascular lesions (35.7% vs 20.6%) and leads to more successful endoscopic treatments 1
• Conventional angiography requires bleeding rates >0.5 mL/min and has only 30-47% sensitivity despite 100% specificity 1

Small Bowel Evaluation

If upper endoscopy and colonoscopy are negative:

• Video capsule endoscopy identifies bleeding sources in 55-65% of patients with obscure GI bleeding 1
• Consider push enteroscopy for proximal jejunal evaluation 1
• In young patients with unexplained bleeding, consider radionuclide scan for Meckel's diverticulum 1

Treatment Strategies

Endoscopic Therapy

• Therapeutic colonoscopy successfully treats focal lesions like angiodysplasias, achieving hemostasis in 39% of severe bleeding cases 5
• For hemorrhoidal bleeding specifically, anoscopic techniques combined with medical management (fiber, adequate water intake) are first-line 1
• Rubber band ligation, sclerotherapy, or other ablative techniques for internal hemorrhoids 1

Angiographic Intervention

• Intra-arterial vasopressin infusion controls bleeding in up to 91% of cases from diverticular disease or angiodysplasia 1
• Major limitation: 50% rebleeding rate after vasopressin cessation 1
• Contraindicated in significant coronary artery disease 1
• Embolization carries 1-4% risk of bowel ischemia 1

Surgical Intervention

Indications for emergency surgery:

• Persistent hemodynamic instability despite aggressive resuscitation 1
• Transfusion requirement >6 units of packed red blood cells 1
• Severe recurrent bleeding 1
• Failure of endoscopic and angiographic therapies 1

Surgical approach depends on etiology:

• For inflammatory bowel disease with massive bleeding: subtotal colectomy with ileostomy 1
• For Crohn's disease: intraoperative ileoscopy to localize bleeding source if not identified preoperatively 1
• Overall operative mortality for emergency lower GI bleeding surgery is 18-25% in patients requiring transfusion 1

Special Populations

Inflammatory Bowel Disease

• Massive bleeding occurs in <6% of IBD cases 1
• Sigmoidoscopy and EGD are appropriate initial studies in stable IBD patients 1
• Angiography/embolization feasibility in IBD remains unclear with limited evidence 1

Anorectal Varices

• Maintain hemoglobin >7 g/dL during resuscitation 1
• Endoscopic variceal ligation, band ligation, or sclerotherapy as first-line treatment 1
• Critical: Perform full colonoscopy if risk factors for colorectal cancer exist, as 2.4-11% of patients with rectal bleeding have CRC 1
• Up to 15% may have upper GI source requiring EGD 1

Young Patients (<50 years)

• More likely to have Dieulafoy's lesion, Crohn's disease, or Meckel's diverticulum 1
• Be aggressive in investigating as small bowel tumors are most common cause of obscure bleeding in this age group 1

Common Pitfalls to Avoid

1. Do not assume bright red blood means distal source - always perform complete evaluation 4
2. Do not rely on clinical history alone to determine need for colonoscopy 2
3. Do not start with flexible sigmoidoscopy - colonoscopy is more effective and cost-efficient 4
4. Do not delay surgery in persistently unstable patients while pursuing diagnostic studies 1
5. Do not overlook upper GI sources - always consider EGD first in significant hematochezia 1