Melena refers to the passage of black, tarry stools, which is typically indicative of gastrointestinal bleeding from an upper GI source. As a junior doctor in the emergency department (ED), understanding the causes, assessment, and management of melena is crucial for effective patient care.
Understanding Melena
Melena results from the digestion of blood as it passes through the gastrointestinal tract. The dark color and tarry consistency are due to the breakdown of hemoglobin by digestive enzymes and bacteria in the intestines. Melena usually indicates bleeding from a source proximal to the ligament of Treitz (esophagus, stomach, or duodenum).
Common Causes of Melena
Peptic Ulcer Disease
Ulcers in the stomach or duodenum can erode into blood vessels, leading to bleeding. Risk factors include Helicobacter pyloriinfection and nonsteroidal anti-inflammatory drug (NSAID) use.
Esophageal Varices
Dilated veins in the esophagus, often due to portal hypertension from liver cirrhosis, can rupture and cause significant bleeding.
Gastritis or Esophagitis
Inflammation of the stomach lining or esophagus can cause bleeding, often related to NSAID use, alcohol consumption, or gastroesophageal reflux disease (GERD).
Mallory-Weiss Tear
A tear at the gastroesophageal junction caused by severe retching or vomiting can lead to upper GI bleeding.
Less Common Causes
Vascular malformations
Malignancies of the stomach or esophagus
Initial Assessment and Management
History Taking
A thorough history is essential to guide further evaluation:
Onset and duration of melena
Associated symptoms such as hematemesis, abdominal pain, dizziness, or syncope
History of liver disease, alcohol use, or NSAID use
Previous episodes of GI bleeding or known ulcers
Physical Examination
The physical examination should focus on identifying signs that may indicate specific causes:
Vital signs: Assess for hypotension and tachycardia indicating hemodynamic instability.
Abdominal examination: Evaluate for tenderness, distension, or signs of liver disease such as ascites.
Skin examination: Look for signs of chronic liver disease like jaundice or spider angiomas.
Diagnostic Workup
Depending on clinical suspicion from history and examination, the following tests may be considered:
Complete Blood Count (CBC): To assess for anemia.
Coagulation Profile: To evaluate clotting status.
Liver Function Tests: If liver disease is suspected.
Blood Type and Crossmatch: In case transfusion is needed.
Upper Endoscopy: To directly visualize and potentially treat the source of bleeding.
Management Strategies
Management of melena in the ED focuses on stabilization and addressing the underlying cause:
Stabilization:
Ensure airway protection if there is a risk of aspiration.
Establish intravenous access for fluid resuscitation with crystalloids.
Transfuse packed red blood cells if there is significant anemia or hemodynamic instability.
Specific Interventions:
Administer proton pump inhibitors (PPIs) intravenously for suspected peptic ulcer bleeding.
Consider octreotide infusion and antibiotics for suspected variceal bleeding.
Urgent endoscopy for diagnosis and treatment (e.g., banding of varices or cauterization of ulcers).
Monitoring and Follow-up:
Continuous monitoring in a high-dependency area for recurrent bleeding.
Referral to gastroenterology for further management after stabilization.
Challenges and Considerations
Melena can indicate significant upper GI bleeding that may lead to hemodynamic instability if not promptly addressed. It is important to differentiate between melena (typically upper GI source) and hematochezia (lower GI source) based on clinical presentation and history. Rapid identification and intervention are crucial to prevent complications such as shock.
By taking a systematic approach to the assessment and management of melena, you can effectively address this condition in the emergency setting while ensuring appropriate follow-up care.
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