Author:

Editor(s):

Updated:

ULY CLINIC

12 Septemba 2025, 00:17:35

Melena

Melena is a clinical sign of upper gastrointestinal (GI) bleeding, characterized by black, tarry stools containing digested blood. The dark color results from bacterial degradation and the action of hydrochloric acid on blood as it travels through the GI tract. At least 60 mL of blood is typically required to produce melena.

Melena usually indicates bleeding from the esophagus, stomach, or duodenum, but can also arise from the jejunum, ileum, or ascending colon. Other causes include swallowed blood, certain medications, or alcohol ingestion. Black stools from substances like lead, iron, bismuth, or licorice are not true melena and should be tested for occult blood.

Severe melena can signal acute bleeding and life-threatening hypovolemic shock, requiring prompt emergency intervention.

History and Physical Examination

Ask the patient when melena was first noticed, its frequency, and quantity.
Inquire about previous episodes and other GI symptoms, such as hematemesis or hematochezia.
Ask about use of NSAIDs, alcohol, or other GI irritants, iron supplements, and anticoagulants (warfarin or herbal).
Inspect the mouth and nasopharynx for signs of bleeding.
Perform a thorough abdominal examination: inspection, auscultation, palpation, and percussion.

Comparing Melena to Hematochezia

Feature	Melena	Hematochezia
Stool Color	Black, tarry	Bright red
Source	Upper GI tract (esophagus, stomach, duodenum)	Lower GI tract (colon, rectum)
Blood Amount	≥60 mL, digested	Variable, often fresh
Onset	Gradual or acute	Usually abrupt
Other Features	May alternate with hematochezia	Often associated with rectal pain

Medical causes

Cause	Typical Presentation / History	Associated Findings
Colon cancer	Right-sided: early melena, abdominal cramping; left-sided: late melena	Weakness, fatigue, anemia, diarrhea or obstipation, anorexia, weight loss
Ebola virus	Abrupt onset fever, headache, malaise, myalgia	Melena, hematemesis, epistaxis, maculopapular rash, dehydration, lethargy
Esophageal cancer	Painless dysphagia progressing to weight loss	Melena late, chest pain, hoarseness, persistent cough, regurgitation
Ruptured esophageal varices	Life-threatening; prior liver disease	Melena, hematochezia, hematemesis, hypotension, tachycardia, agitation
Gastritis / Peptic ulcer	Epigastric discomfort, nausea, vomiting	Melena, hematemesis, heartburn, possible hypovolemic shock
Mallory-Weiss syndrome	Post-vomiting upper GI bleed	Melena, hematemesis, epigastric/back pain, shock signs
Mesenteric vascular occlusion	Persistent abdominal pain 2–3 days	Melena, tenderness, guarding, distention, anorexia, vomiting, fever, shock
Small-bowel tumors	Abdominal pain, distention	Melena, increasing bowel sounds
Thrombocytopenia	Bleeding tendencies	Melena, hematemesis, epistaxis, petechiae, ecchymoses, hematuria, fatigue
Typhoid fever / Yellow fever	Fever, headache, malaise	Late melena, hypotension, hypothermia, jaundice, epistaxis, mucosal hemorrhage

Other causes

Drugs and alcohol: Aspirin, NSAIDs, and alcohol may cause melena by gastric irritation.

Emergency interventions

Monitor orthostatic vital signs for hypovolemic shock (↓10 mmHg systolic or ↑10 bpm pulse).
Look for tachycardia, tachypnea, cool/clammy skin.
Establish a large-bore IV line for fluids and transfusions.
Obtain hematocrit, coagulation studies (PT, INR, PTT).
Place the patient flat with head turned to the side, feet elevated.
Administer supplemental oxygen as needed.

Special considerations

Encourage bed rest and keep the perianal area clean.
Nasogastric tube may assist with gastric drainage and decompression.
Prepare for diagnostic studies: blood tests, endoscopy, barium swallow, upper GI series, and blood transfusions as indicated.

Patient counseling

Report any changes in bowel elimination.
Avoid aspirin, other NSAIDs, and alcohol.
Emphasize the importance of screening for colorectal cancer.

Pediatric pointers

Neonates: Melena neonatorum may occur due to extravasated blood in the alimentary canal.
Older children: Common causes include peptic ulcer, gastritis, or Meckel’s diverticulum.

Geriatric pointers

Elderly patients with recurrent, unexplained GI bleeding may require angiography or exploratory laparotomy if anemia risk outweighs procedural risks.

References

Miheller P, Kiss LS, Juhasz M, Mandel M, Lakatos PL. Recommendations for identifying Crohn’s disease patients with poor prognosis. Expert Rev Clin Immunol. 2013;9:65–76.
Pariente B, Cosnes J, Danese S, Sandborn WJ, Lewin M, Fletcher JG, et al. Development of the Crohn’s disease digestive damage score, the Lémann score. Inflamm Bowel Dis. 2011;17(6):1415–1422.