How to manage melena (black, tarry stools) in a patient?

Management of Melena (Black, Tarry Stools)

Patients presenting with melena require prompt endoscopic assessment to identify and treat the bleeding source, as this represents upper gastrointestinal bleeding until proven otherwise. 1

Initial Assessment and Urgent Endoscopy

• Perform urgent esophagogastroduodenoscopy (EGD) within 24 hours for patients with acute severe bleeding presenting as hematemesis or melena 1
• The upper gastrointestinal tract is the most common source of melena, with peptic ulcer disease accounting for 35-50% of cases, followed by gastroduodenal erosions (8-15%), esophagitis (5-15%), and varices (5-10%) 1
• Melena indicates more severe bleeding than isolated symptoms, particularly when accompanied by hematemesis 1
• In patients with obscure gastrointestinal bleeding, the presence of melena doubles the odds of finding a bleeding source in the proximal small intestine 2

Endoscopic Management Options

Available endoscopic therapies include:

• Injection therapy at the bleeding site 1
• Mechanical therapy such as endoscopic clip placement 1
• Ablative therapy including argon plasma coagulation or laser therapy 1
• Combination of multiple modalities for optimal hemostasis 1

Critical caveat: While endoscopic treatment may be effective initially, the rate of recurrent bleeding in gastric cancer patients is very high 1

Pharmacologic Acid Suppression

Initiate high-dose proton pump inhibitor (PPI) therapy immediately:

• Omeprazole 40 mg once daily orally or intravenously twice daily 1, 3
• Pantoprazole 40 mg once daily 3, 4
• Ranitidine 300 mg orally twice daily (if PPI unavailable) 1
• Cimetidine 400 mg orally or intravenously four times daily 1

PPIs are the most potent gastric acid-suppressing agents and are more effective than H2-receptor antagonists for healing peptic ulcers and reducing rebleeding risk 3

Alternative Interventions When Endoscopy Fails

If endoscopic therapy is unsuccessful or unavailable:

• Interventional radiology with angiographic embolization techniques 1
• External beam radiation therapy (EBRT) for both acute and chronic gastrointestinal bleeding 1

Further Evaluation if EGD is Nondiagnostic

If initial EGD reveals no bleeding source:

• Consider colonoscopy, though diagnostic yield is low (4.8%) for melena after nondiagnostic EGD 5
• The rate of therapeutic intervention during colonoscopy for this indication is only 1.7% 5
• Capsule endoscopy should be performed if both EGD and colonoscopy are negative, as small bowel sources account for approximately 5% of melena cases 6
• When capsule endoscopy is used for obscure bleeding with melena, begin deep enteroscopy with an antegrade (push enteroscopy) approach, as bleeding is more likely proximal 2

Monitoring for Rebleeding

Define rebleeding as:

• Fresh hematemesis and/or melena PLUS
• Development of shock (pulse >100 bpm, systolic BP <100 mmHg) OR
• Fall in central venous pressure >5 mmHg OR
• Reduction in hemoglobin >20 g/L over 24 hours 1

Always confirm suspected rebleeding with repeat endoscopy 1

Special Populations

In pediatric patients with melena:

• Vomiting, abnormal abdominal ultrasound findings, and hemoglobin ≥3 g/dL below normal limit are significant predictors that EGD will identify the bleeding source 6
• Duodenal ulcer is the most common diagnosis in children, followed by gastric ulcer, esophagitis, and esophageal varices 6

Common pitfall: Do not assume melena always originates from the upper GI tract—small bowel and even right-sided colonic sources can present with melena, particularly arteriovenous malformations, colitis, large polyps (≥20 mm), tumors, or ulcers 5