What is the diagnostic and treatment approach for a patient presenting with hematochezia (blood in stool)?

Diagnostic and Treatment Approach for Hematochezia

For patients presenting with hematochezia (blood in stool), colonoscopy is recommended as the first-line diagnostic procedure after hemodynamic stabilization, with complete examination to the cecum to identify the bleeding source. 1, 2

Initial Assessment and Stabilization

• Hemodynamic Assessment:

  • Maintain hemoglobin level ≥7 g/dL (target 7-9 g/dL)
  • Ensure mean arterial pressure >65 mmHg while avoiding fluid overload
  • Correct any coagulopathy, especially in patients on anticoagulants 1

• Risk Stratification:

  • Check vital signs, hemoglobin, hematocrit, and coagulation parameters
  • For severe bleeding: perform blood typing and cross-matching 2
  • Consider upper GI source in patients with severe hematochezia and hypovolaemia (found in 10-15% of such cases) 2

Diagnostic Algorithm

1. Rule out upper GI source:

   • Perform nasogastric lavage if medium to low suspicion of upper GI source
   • If blood/coffee grounds in aspirate, perform upper endoscopy 2
   • Consider upper endoscopy in patients with risk factors for peptic ulcer, portal hypertension, or angiodysplasia 2

2. Lower GI evaluation:

   • Colonoscopy is the diagnostic procedure of choice with 72-86% diagnostic accuracy 2
   • Should be performed after adequate bowel preparation
   • Complete to cecum with high-quality examination 2
   • Perform within 24 hours of presentation for active bleeding 1

3. If colonoscopy is negative:

   • Consider video capsule endoscopy (VCE) if small bowel source is suspected 1
   • CT angiography for detecting bleeding at rates of 0.3-1.0 mL/min 1

Common Causes of Hematochezia and Management

1. Hemorrhoids

• Diagnostic approach: Digital rectal examination and anoscopy 2
• Management:
  • Non-operative first-line therapy with dietary and lifestyle changes (increased fiber and water intake)
  • Flavonoids to relieve symptoms
  • Topical muscle relaxants for thrombosed/strangulated hemorrhoids 2

2. Diverticular Bleeding

• Diagnostic approach: Colonoscopy (60% from left colon when diagnosed by colonoscopy) 2
• Management:
  • Endoscopic intervention for active bleeding
  • Angiographic embolization if endoscopic treatment fails 1

3. Angiodysplasia

• Diagnostic approach: Colonoscopy (sensitivity >80% when colon examined completely) 2
  • Most common in cecum and proximal ascending colon (54%)
  • Consider administering naloxone to enhance visualization if patient received narcotics 2
• Management:
  • Endoscopic ablation for accessible lesions
  • Angiographic embolization if endoscopic treatment fails 1

4. Anorectal Varices

• Diagnostic approach: Proctoscopy/anoscopy to distinguish from hemorrhoids 2
• Management:
  • Local procedures: endoscopic variceal ligation, band ligation, sclerotherapy, or EUS-guided glue injection
  • Multidisciplinary approach involving hepatology team
  • Intravenous fluid replacement, blood transfusion, correction of coagulopathy, and portal hypertension medication 2

5. Colorectal Cancer

• Risk factors to consider:
  • Hematochezia confers a hazard ratio of 10.66 for early-onset colorectal cancer
  • Iron deficiency anemia confers a hazard ratio of 10.81 for early-onset colorectal cancer
  • Unexplained weight loss of ≥5 kg within 5 years (odds ratio 2.23) 2
• Management: Depends on cancer stage and location

Special Considerations

Inflammatory Bowel Disease

• Consider chromoendoscopy for patients with IBD due to increased risk of colorectal cancer 3

Age Considerations

• Colonoscopy yield for cancer in bleeding indications: 1 per 9-13 colonoscopies 4
• Even in young patients (<50 years), hematochezia may be associated with colorectal cancer 5

Follow-up and Prevention

• Iron supplementation for patients discharged with anemia (80-90% response rate) 1
• Gastroenterology follow-up within 2 weeks if discharged
• Consider screening for H. pylori and eradication if positive 1

Common Pitfalls to Avoid

1. Delaying colonoscopy in patients with hematochezia - this can lead to advanced-stage disease if colorectal cancer is present 2

2. Assuming hemorrhoids are the cause without complete evaluation - multiple studies show physicians cannot reliably distinguish between benign and significant causes of hematochezia by history alone 6

3. Using FIT testing for symptomatic patients - this may lead to diagnostic delays as a positive result would still require colonoscopy 2

4. Incomplete colonoscopy - examination should be complete to the cecum as right-sided lesions may be missed 2

5. Performing colonoscopy without adequate resuscitation - ensure hemodynamic stability first 2