Melena (Black Stool) – Definition, Causes, and Treatment

Melena is an important clinical sign characterized by the passage of black, shiny, sticky stools, resembling tar. This symptom is usually the result of bleeding in the upper gastrointestinal tract, where the blood is digested and altered by digestive enzymes, giving the stool its characteristic appearance. The term “melena” comes from Greek and means “black as pitch.”

In this article, we will discuss the possible causes of melena, its clinical significance, associated conditions such as peptic ulcer, esophageal varices, or gastrointestinal tumors, as well as the importance of prompt medical evaluation for an accurate diagnosis and appropriate treatment.

What is Melena and How Does it Manifest?

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Melena is the medical term for the passage of black, shiny, tar-like stools caused by the presence of digested blood in the upper gastrointestinal tract. In this article, we will discuss what melena is, how it manifests, and its clinical significance.

This symptom occurs when blood from the esophagus, stomach, or duodenum is exposed to gastric acid and digestive enzymes, resulting in the transformation of hemoglobin into hematin, a dark pigment. Consequently, the stool takes on a deep black color and characteristic sticky consistency.

Melena is not a disease but an important clinical sign that can indicate potentially serious internal bleeding. Not all dark-colored stools are melena; iron supplements, bismuth, or certain pigmented foods can temporarily color the stool without the typical tarry appearance.

Cases of melena require emergency medical evaluation, as they may indicate underlying conditions such as gastric ulcers, esophageal varices, or digestive tumors. Proper diagnosis and timely intervention can prevent severe complications and ensure adequate treatment.

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Photo source: Aronia-charlottenburg.ro

Main Causes of Melena

Melena is caused by bleeding in the upper gastrointestinal tract, usually in the stomach, duodenum, or esophagus. This bleeding leads to the presence of digested blood in the stool, giving it a black, shiny, and sticky appearance.

The most common causes of melena include:

• Peptic ulcer – lesions on the lining of the stomach or duodenum, often associated with Helicobacter pylori infection or the use of nonsteroidal anti-inflammatory drugs (NSAIDs);
• Gastritis – inflammation of the stomach lining, which can cause superficial bleeding, often triggered by alcohol, stress, or irritating medications;
• Esophageal varices – swollen veins in the esophagus, typically occurring in patients with liver cirrhosis, which can bleed profusely;
• Mallory-Weiss syndrome – tears in the lining of the esophagus caused by repeated or forceful vomiting;
• Esophagitis – inflammation of the esophagus, often caused by severe gastroesophageal reflux disease;
• Tumors – benign or malignant growths in the esophagus, stomach, or upper small intestine, which can bleed chronically or intermittently.

Less common causes may include trauma, vascular malformations, coagulation disorders, or the use of anticoagulant or antiplatelet medications (such as aspirin, heparin, or warfarin), which increase the risk of gastrointestinal bleeding.

In all these situations, the presence of black stools requires prompt medical evaluation to identify the cause and initiate appropriate treatment.

Symptoms Associated with Melena

Melena itself is a symptom characterized by black, shiny, sticky stools, indicating the presence of digested blood in the upper gastrointestinal tract.

Other symptoms that may accompany melena and provide clues about the severity of bleeding include:

• Fatigue and weakness – often occur in the context of anemia caused by blood loss, especially if it is chronic;
• Dizziness – a drop in blood pressure, particularly when suddenly standing up (orthostatic hypotension), is a sign that the body is losing blood volume;
• Pallor – a pale face or light skin color indicates reduced oxygenation of tissues due to hemorrhage;
• Fainting (syncope) – in severe cases of melena, a sudden drop in blood pressure and blood flow can lead to loss of consciousness;
• Abdominal pain – localized in the epigastrium or substernal region, it can indicate a gastric or duodenal ulcer, or another source of bleeding;
• Shortness of breath – severe anemia can lead to a feeling of breathlessness, especially during exertion;
• Hematemesis – vomiting bright red blood (active bleeding) or “coffee grounds” (partially digested blood), a symptom often associated with melena;
• Cold sweats, rapid and weak pulse, confusion, or agitation – these are signs of hypovolemic shock and require emergency medical intervention.

The presence of these symptoms, especially in combination with the characteristic stool appearance, requires prompt medical evaluation. Even if not all individuals experience the listed symptoms, identifying melena necessitates determining the cause and initiating treatment.

Diagnosing Melena

Melena is diagnosed by a gastroenterologist. Confirmation of the diagnosis involves careful clinical evaluation, supplemented by paraclinical investigations and endoscopic explorations, to identify the source of bleeding in the upper digestive tract.

The following may be necessary for diagnosis:

• Stool examination – a sample can be collected to test for digested blood. Fecal occult blood testing is useful in cases where melena is not obvious to the naked eye.
• Nasogastric tube placement – used to check for the presence of blood in the stomach, especially in emergencies, by aspirating gastric contents.
• Upper gastrointestinal endoscopy (EGD) – the standard procedure for direct visualization of the esophagus, stomach, and duodenum. It allows for the identification and treatment of the bleeding source, as well as the collection of biopsies if tumorous lesions are suspected.
• Capsule endoscopy – involves swallowing a video capsule to explore the small intestine, useful in cases where bleeding has not been identified by conventional endoscopy.
• Blood tests – a complete blood count may indicate anemia (low hemoglobin), while coagulation tests and liver function tests provide additional information about the patient’s general condition.
• Imaging studies – in specific situations, computed tomography (CT) scans, magnetic resonance imaging (MRI) with vascular sequences, or angiography may be used, particularly in cases of active, endoscopically unidentified bleeding.
• Abdominal ultrasonography – may reveal associated pathologies, such as liver cirrhosis or gallstones.

Differential diagnosis may reveal:

• False melena – occurs when stool is colored black due to the consumption of iron supplements, medicinal charcoal, or foods like blueberries and beetroot.
• Swallowed bleeding – from the mouth or respiratory tract (hemoptysis) can give an appearance similar to melena but has an extradigestive origin.

Treatment Options for Black Tarry Stools (Melena)

The treatment of melena directly depends on the underlying cause of the bleeding. Hemodynamic stabilization is the immediate priority, especially in cases of heavy bleeding from the upper gastrointestinal tract.

Initial measures consist of:

• Intravenous fluid administration (infusion) – to restore circulating volume and prevent hypovolemic shock.
• Blood transfusions – indicated if the patient has severe anemia or circulatory instability.

Etiological treatment is adapted according to the cause of bleeding and includes:

• Medication therapy:
  • Proton pump inhibitors (PPIs), such as omeprazole or pantoprazole – reduce gastric acidity and promote the healing of lesions like peptic ulcers or gastritis;
  • Antibiotics – administered in cases of Helicobacter pylori infection, which must be eradicated;
  • Hemostatic agents – may be used to reduce bleeding;
  • Discontinuation or adjustment of anticoagulant/antiplatelet treatments, where necessary, depending on the bleeding vs. thrombotic risk ratio.
• Endoscopic interventions:
  • Local injection with vasoconstrictive agents;
  • Cauterization (thermal therapy);
  • Application of hemostatic clips;
  • Esophageal band ligation, especially for esophageal varices;
  • Spraying of hemostatic agents – for diffuse bleeding.
• Surgical treatment:
  • In cases where bleeding cannot be stopped endoscopically or if there are large structural lesions (perforated ulcer, tumors, vascular malformations), surgery may be necessary to resect the affected area or for porto-systemic shunts (in cases of hemorrhagic esophageal varices).
• Supportive therapy:
  • Administration of oral or intravenous iron, depending on the severity of anemia;
  • Correction of other metabolic or functional imbalances.
• Treatment of the underlying disease:
  • If bleeding is caused by a systemic condition, such as liver disease or chronic kidney disease, treating these conditions is essential to prevent recurrences.

Post-treatment monitoring is based on:

• periodic check-ups;
• endoscopic reassessment, if necessary;
• counseling on warning signs and lifestyle modifications (alcohol, NSAIDs, etc.).

Therefore, the therapeutic approach to melena is multidisciplinary and tailored to each individual case, aiming to ensure patient stability, stop bleeding, and prevent recurrence.

In Which Situations Is Urgent Medical Consultation Necessary?

Recognizing warning signs in cases of melena is essential for preventing serious complications. Black, shiny stools observed in adults can indicate upper gastrointestinal bleeding, which requires emergency medical intervention.

Situations when immediate medical help should be sought include:

• Presence of hemodynamic instability symptoms
  • pronounced dizziness;
  • feeling faint;
  • rapid and weak pulse;
  • low blood pressure;
  • cold sweats;
  • confusion or agitation.
    These indicate significant blood loss and require emergency treatment in a specialized facility.
• Vomiting blood (hematemesis)
  • either fresh blood or “coffee grounds” appearance;
  • its association with melena signals active bleeding in the upper digestive tract.
• Severe abdominal pain
  • if it is sudden in onset or progressively worsening, it may suggest complications such as a perforated ulcer or intestinal obstruction, requiring prompt surgical intervention.
• History of gastrointestinal conditions
  • individuals with peptic ulcer, esophageal varices, or Crohn’s disease should seek immediate medical attention upon the appearance of melena, even if they do not present other obvious symptoms.
• Treatment with anticoagulant or NSAID medications
  • the use of these substances increases the risk of gastrointestinal bleeding. The appearance of black stools in this context requires urgent evaluation and adjustment of treatment under medical supervision.
• Recurrent or persistent melena
  • even in the absence of severe symptoms, chronic bleeding can lead to severe anemia and may mask serious illnesses requiring specialized diagnosis and treatment.

Conclusions

In conclusion, black stool, especially when accompanied by systemic symptoms, should not be ignored. Early evaluation and prompt intervention can prevent the worsening of the clinical condition and reduce the risk of potentially fatal complications.

Disclaimer! The information presented in this article is for informational and educational purposes only. It does not substitute for professional medical advice, diagnosis, or treatment recommended by a physician. If you experience the described symptoms, such as black stools, dizziness, or other signs of internal bleeding, seek immediate medical attention. Any decision regarding your health should be made after a clinical evaluation by a qualified professional.

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