Melena (black stool) - Causes, Treatment & When to See a Doctor

```html

What is Melena (black stool)?

Melena refers to the passage of dark, tar‑like, and often foul‑smelling stool. The characteristic black color is caused by the digestion of blood that has been exposed to gastric acid and intestinal enzymes. Because blood changes color as it travels through the gastrointestinal (GI) tract, melena usually indicates that bleeding is occurring **proximal to the ligament of Treitz** (the point where the duodenum ends and the jejunum begins) – that is, in the esophagus, stomach, or the first part of the small intestine.

Although melena is a visible sign that something is bleeding inside the GI tract, the amount of blood loss can vary widely—from a few milliliters to several hundred milliliters. Small, chronic bleeds may show up as melena for weeks before a person notices other symptoms, while massive bleeds can produce melena rapidly and be life‑threatening.

Understanding melena is important because it often serves as an early warning sign of gastrointestinal disease, medication side effects, or systemic conditions that need prompt evaluation.

Common Causes

Melena can result from many different conditions. Below are the most frequent causes, grouped by organ system.

• Peptic ulcer disease (PUD) – erosions in the stomach or duodenum caused by Helicobacter pylori infection or chronic NSAID use.
• Gastric or duodenal erosions – superficial breaks in the mucosa from severe stress (e.g., critical illness, burns) or alcohol.
• Esophageal varices – dilated veins in the esophagus that can rupture in patients with advanced liver disease.
• Gastric cancer – malignant tumors can ulcerate and bleed.
• Gastrointestinal stromal tumors (GIST) or other submucosal masses – may erode into the lumen.
• Medication‑induced injury – especially non‑steroidal anti‑inflammatory drugs (NSAIDs), aspirin, anticoagulants, and selective serotonin reuptake inhibitors (SSRIs).
• Dieulafoy lesion – an abnormally large submucosal artery that can erode and cause brisk bleeding.
• Vascular malformations – such as angiodysplasia of the small intestine.
• Infectious causes – e.g., severe gastritis from Helicobacter pylori, cytomegalovirus (CMV) in immunocompromised patients.
• Rare systemic diseases – such as hereditary hemorrhagic telangiectasia (HHT) or vasculitis (e.g., Henoch‑Schönlein purpura).

Associated Symptoms

Because melena signals GI bleeding, other symptoms often accompany it, reflecting the location or severity of the bleed.

• Abdominal pain or discomfort (often epigastric in peptic ulcer disease).
• Nausea or vomiting, sometimes with visible blood (hematemesis).
• Feeling light‑headed, dizzy, or faint, especially when standing (orthostatic symptoms).
• Fatigue, weakness, or shortness of breath due to anemia.
• Unexplained weight loss.
• Jaundice or swelling of the abdomen/legs (may suggest underlying liver disease and varices).
• Fever or chills if infection or inflammation is present.
• Change in stool consistency – tarry, sticky, or “coffee‑ground” appearance.

When to See a Doctor

Melena should never be ignored. Seek medical attention promptly if any of the following occur:

• Black, tarry stool that persists for more than 24 hours.
• Accompanying symptoms such as vomiting blood, severe abdominal pain, or fainting.
• Signs of anemia (pale skin, rapid heartbeat, shortness of breath on exertion).
• Recent use of NSAIDs, aspirin, anticoagulants, or antiplatelet drugs.
• History of liver disease, known ulcers, or prior GI bleeding.
• Sudden onset of melena after a trauma or injury.

Even if you feel otherwise well, a single episode of melena warrants a medical evaluation because underlying conditions can progress silently.

Diagnosis

Doctors use a stepwise approach that combines a detailed history, physical examination, and targeted tests.

1. History and Physical Exam

• Medication review (especially NSAIDs, anticoagulants, PPIs).
• Alcohol consumption, smoking, and dietary habits.
• Previous GI problems, liver disease, or surgeries.
• Physical signs of anemia (pallor), volume depletion (dry mucous membranes), or liver disease (spider angiomas, ascites).

2. Laboratory Tests

• Complete blood count (CBC) – looks for low hemoglobin/hematocrit.
• Iron studies – assess chronic blood loss.
• Blood urea nitrogen (BUN) / creatinine ratio – an elevated BUN relative to creatinine may suggest upper GI bleed.
• Coagulation profile (PT/INR, aPTT) if anticoagulation is a concern.

3. Endoscopic Evaluation

• Upper endoscopy (EGD) – first‑line test to visualize the esophagus, stomach, and duodenum; can also provide therapeutic interventions (e.g., clipping, cautery).
• Colonoscopy – generally reserved for lower GI sources but may be performed if upper endoscopy is negative and bleeding persists.

4. Imaging Studies

• CT angiography – detects active bleeding when endoscopy is inconclusive.
• Radionuclide bleeding scan (technetium‑99m‑labeled red blood cells) – highly sensitive for slow bleeds.
• Capsule endoscopy – useful for small‑bowel sources not reachable by standard endoscopy.

5. Additional Tests

• Helicobacter pylori testing (urea breath test, stool antigen, or biopsy).
• Liver function tests and ultrasound if varices are suspected.

Treatment Options

Treatment is directed at both stopping the bleed and addressing the underlying cause.

1. Stabilization

• Intravenous (IV) fluids to correct volume depletion.
• Blood transfusion if hemoglobin < 7 g/dL (or higher thresholds in patients with cardiovascular disease).
• IV proton‑pump inhibitors (PPIs) such as pantoprazole 80 mg bolus followed by 8 mg/hour infusion – reduces gastric acid and stabilizes clot formation.

2. Endoscopic Therapy

• Thermal coagulation, hemoclipping, or injection of epinephrine to control active bleeding.
• Band ligation for esophageal varices.

3. Pharmacologic Management

• Eradication of H. pylori with triple therapy (clarithromycin‑based) or quadruple therapy.
• Discontinue or switch offending NSAIDs; consider alternative pain relievers (acetaminophen).
• For anticoagulant‑related bleeds, reverse agents (e.g., vitamin K, protamine, idarucizumab) may be required.
• Non‑selective beta‑blockers (e.g., propranolol) for portal hypertension to reduce variceal pressure.

4. Surgical or Radiologic Intervention

• When endoscopic control fails, angiographic embolization or surgical resection may be necessary.

5. Home Care & Follow‑up

• Adhere to prescribed PPIs for 4–8 weeks (or longer if ulcer healing is required).
• Complete the full course of H. pylori eradication therapy.
• Monitor stool color daily for recurrence.
• Schedule follow‑up endoscopy if indicated (usually 6–8 weeks after an ulcer bleed).

Prevention Tips

While some causes (e.g., cancer) cannot be fully prevented, many risk factors for melena are modifiable.

• Use NSAIDs judiciously – take the lowest effective dose, use with food, and consider gastro‑protective agents (PPIs) if long‑term use is needed.
• Limit alcohol intake – excessive alcohol irritates the gastric mucosa.
• Quit smoking – smoking impairs ulcer healing and increases risk of recurrence.
• Maintain a healthy weight and balanced diet – reduces reflux and ulcer risk.
• Screen for and treat H. pylori infection, especially in patients with a history of ulcers.
• For patients with chronic liver disease:
  • Regularly undergo surveillance endoscopy for varices.
  • Adhere to beta‑blocker therapy if prescribed.
  • Avoid hepatotoxic substances (excess alcohol, illicit drugs).
• Review all medications with your healthcare provider, especially if you are on blood thinners or antiplatelet drugs.
• Stay up to date with vaccinations (e.g., hepatitis B) to prevent liver disease that can lead to varices.

Emergency Warning Signs

Melena is a visible sign that gastrointestinal bleeding is occurring. Prompt evaluation, appropriate treatment, and addressing modifiable risk factors can dramatically improve outcomes and prevent recurrence. If you notice black, tarry stools, do not wait—contact your healthcare provider right away.

---

Sources: Mayo Clinic. “Melena.”; American College of Gastroenterology Guidelines for Upper GI Bleeding (2023); CDC – Alcohol and Gastrointestinal Health; NIH – Helicobacter pylori Treatment Recommendations; WHO – Global Guidelines on Safe Use of NSAIDs; Cleveland Clinic – Upper GI Bleeding Overview.

```