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Gastrointestinal Bleed (Melena)

What is Gastrointestinal bleed (melena)?

Melena describes black, tar‑like stools that have a distinct, foul odor. The dark colour results from the digestion of blood as it passes through the intestines, most commonly indicating bleeding from the upper gastrointestinal (GI) tract—​the esophagus, stomach, or duodenum. While melena is a sign of a GI bleed, not every GI bleed presents with melena; lower GI sources often produce bright‑red or maroon stools (hematochezia).

Bleeding can be acute (sudden, large volume) or chronic (slow, small amounts over weeks). Chronic bleeding may lead to iron‑deficiency anemia before the stool colour change is even noticed.

Key points:

• Melena is a clinical clue, not a diagnosis.
• It usually signals a bleed proximal to the ligament of Treitz, but severe lower‑GI bleeding can also turn the stool black if transit time is long enough.
• Other causes of black stool include iron supplements, bismuth‑containing medications (e.g., Pepto‑Bismol), or certain foods (black licorice, blueberries). A medication or dietary cause should be considered when melena appears without other red‑flag symptoms.

Understanding the underlying cause is essential because treatment ranges from simple medication adjustments to urgent endoscopic or surgical intervention.

Common Causes

Below are the most frequent conditions that can produce melena. They are grouped by anatomical region and pathophysiology.

• Peptic ulcer disease (PUD) – Erosion of the stomach or duodenal lining, often related to Helicobacter pylori infection or chronic NSAID use.
• Gastric erosions & gastritis – Inflammation or superficial injury of the gastric mucosa, which can be caused by alcohol, stress, or medications.
• Esophageal varices – Dilated veins in the esophagus caused by portal hypertension (commonly from cirrhosis). Rupture leads to massive upper‑GI bleeding.
• Mallory‑Weiss tears – Longitudinal mucosal lacerations at the gastro‑esophageal junction after severe vomiting or retching.
• Erosive duodenitis – Inflammation of the duodenum, often NSAID‑related.
• Gastrointestinal malignancies – Gastric or duodenal adenocarcinoma, gastrointestinal stromal tumors (GIST), or carcinoid tumors can ulcerate and bleed.
• Angiodysplasia – Fragile, dilated vessels in the mucosa of the stomach or small intestine that can intermittently bleed.
• Dieulafoy lesion – An abnormally large arterial vessel protruding through a tiny mucosal defect, most often in the stomach.
• Hemobilia – Bleeding into the biliary tree from trauma, liver biopsy, or gallstone disease; blood can pass into the duodenum and produce melena.
• Medication‑induced injury – Chronic use of NSAIDs, aspirin, anticoagulants (warfarin, DOACs), or corticosteroids can erode the mucosa and precipitate bleeding.

Associated Symptoms

Melena rarely occurs in isolation. The following symptoms often accompany a GI bleed and help clinicians gauge severity.

• Abdominal pain or discomfort – May be epigastric in peptic ulcer disease or diffuse in gastritis.
• Nausea and vomiting – Especially if the bleed is brisk; vomitus may contain blood (hematemesis) which can be bright red or coffee‑ground appearing.
• Dizziness, light‑headedness, or syncope – Signs of hypovolemia or anemia.
• Fatigue or weakness – Resulting from anemia, especially with chronic occult bleeding.
• Shortness of breath – Due to decreased oxygen‑carrying capacity.
• Pallor – Notable in the skin, conjunctiva, or nail beds.
• Palpitations – When the heart compensates for low blood volume.
• Weight loss – May indicate an underlying malignancy or chronic inflammation.

When to See a Doctor

Because melena signals bleeding somewhere in the GI tract, prompt medical attention is usually warranted. Seek care if you notice any of the following:

• Black, tarry stools lasting longer than 24 hours.
• Accompanying vomiting of blood or material that looks like coffee grounds.
• Sudden dizziness, fainting, or feeling “light‑headed” when standing.
• Rapid heart rate (tachycardia) or low blood pressure (hypotension).
• Severe abdominal pain that does not improve.
• Signs of anemia such as persistent fatigue, shortness of breath on minimal exertion, or noticeable pallor.
• Recent use of blood‑thinning medication (warfarin, clopidogrel, DOACs) combined with melena.

Even if you feel otherwise well, a new onset of melena should be evaluated because hidden blood loss can progress silently.

Diagnosis

Diagnosing the source of melena involves a stepwise approach that combines history, physical examination, laboratory studies, and imaging.

1. Clinical History & Physical Exam

• Ask about NSAID, aspirin, anticoagulant, or alcohol use.
• Inquire about prior peptic ulcer disease, liver disease, or known GI malignancy.
• Check vital signs for hypotension or tachycardia.
• Examine the abdomen for tenderness, masses, or organomegaly.

2. Laboratory Tests

• Complete blood count (CBC) – Detects anemia (low hemoglobin/hematocrit) and assesses platelet count.
• Basic metabolic panel (BMP) – Evaluates electrolytes and kidney function, important before contrast imaging.
• Coagulation profile (PT/INR, aPTT) – Determines bleeding risk, especially if the patient is on anticoagulants.
• Blood type & cross‑match – Preparedness for possible transfusion.
• Fecal occult blood test (FOBT) or fecal immunochemical test (FIT) – May be used if melena is questionable, but direct visualization is preferred.

3. Endoscopic Evaluation

• Upper endoscopy (esophagogastroduodenoscopy, EGD) – First‑line test for melena; allows visualization of the esophagus, stomach, and duodenum, and enables therapeutic interventions (e.g., clipping, injection, cautery).
• Colonoscopy – Considered if the EGD is negative and the bleed may be from the colon or if melena is suspected to be due to rapid transit of lower‑GI blood.

4. Imaging Studies

• CT angiography – Detects active arterial bleeding and can guide interventional radiology.
• Tagged red blood cell scan – Sensitive for low‑rate bleeding (0.1 mL/min) but less specific.
• Capsule endoscopy – Helpful for obscure small‑bowel sources when EGD and colonoscopy are unrevealing.

5. Additional Tests

• Helicobacter pylori testing (urea breath test, stool antigen, or biopsy) – Important if ulcer disease is suspected.
• Liver function tests & ultrasound – Assess for cirrhosis or portal hypertension when varices are a concern.

Treatment Options

Treatment is directed at two goals: stabilizing the patient and stopping the bleeding at its source. The approach varies with severity, underlying cause, and comorbidities.

1. Acute Stabilization

• Fluid resuscitation – Intravenous isotonic crystalloids (e.g., normal saline) to maintain blood pressure.
• Blood transfusion – Packed red blood cells if hemoglobin <7–8 g/dL (or higher threshold in patients with cardiovascular disease).
• Correction of coagulopathy – Vitamin K, fresh frozen plasma, or prothrombin complex concentrate for warfarin‑related bleeding; reversal agents for DOACs (e.g., idarucizumab for dabigatran).
• Proton pump inhibitor (PPI) infusion – High‑dose IV pantoprazole or omeprazole reduces gastric acidity, stabilizes clots and is standard after an upper GI bleed.

2. Endoscopic Therapy

• Thermal coagulation, hemoclips, or injection of epinephrine for ulcer or Dieulafoy lesions.
• Band ligation or sclerotherapy for esophageal varices.
• Argon plasma coagulation (APC) for angiodysplasia.

3. Pharmacologic Management (Long‑Term)

• Eradication of H. pylori – Triple therapy (PPI + clarithromycin + amoxicillin/metronidazole) for 14 days.
• Maintenance PPI therapy – For patients with recurrent ulcer disease or NSAID‑induced gastritis.
• Non‑selective beta‑blockers (e.g., propranolol, nadolol) – Reduce portal pressure and prevent variceal re‑bleeding.
• Discontinuation or dose reduction of NSAIDs / aspirin – Substitute with acetaminophen or COX‑2 selective agents if analgesia is needed.

4. Radiologic & Surgical Interventions

• Transarterial embolization (TAE) – Interventional radiology technique to occlude bleeding vessels when endoscopy fails.
• Surgical resection – Reserved for uncontrolled bleeding, perforated ulcers, or tumors not amenable to endoscopic therapy.

5. Home Care & Lifestyle Measures

• Adopt a low‑irritant diet—avoid spicy foods, alcohol, and caffeine until the ulcer heals.
• Take medications with food to minimize gastric irritation.
• Maintain adequate iron intake (red meat, leafy greens, fortified cereals) or supplements after the bleed resolves, especially if anemia was present.
• Follow up with your gastroenterologist within 1–2 weeks after discharge to confirm healing and adjust therapy.

Prevention Tips

Many causes of melena are modifiable. Consider the following steps to reduce risk.

• Use the lowest effective dose of NSAIDs and always take them with food or a PPI if prolonged use is unavoidable.
• Limit alcohol consumption—excessive intake damages the gastric mucosa and heightens variceal risk in liver disease.
• Screen for and eradicate H. pylori if you have a history of dyspepsia, ulcer disease, or belong to a high‑prevalence region.
• Manage chronic liver disease through lifestyle changes, antiviral therapy for hepatitis B/C, and regular surveillance for varices.
• Take anticoagulants under close medical supervision; report any gastrointestinal symptoms promptly.
• Adopt a balanced diet rich in fiber to support overall GI health.
• Regular medical check‑ups—especially if you have known risk factors such as prior ulcers, cirrhosis, or inflammatory bowel disease.
• Consider daily low‑dose aspirin only if prescribed for cardiovascular protection; discuss alternatives with your physician if you have a bleeding tendency.

Emergency Warning Signs

Key Takeaways

Melena is a visual cue that blood is traversing the gastrointestinal tract, most often from an upper‑GI source. While it can be caused by relatively benign conditions such as a mild gastritis, it may also herald serious pathology like peptic ulcer perforation or variceal hemorrhage. Early recognition, prompt medical evaluation, and appropriate treatment dramatically lower the risk of complications such as severe anemia, shock, or death.

Always seek professional care if you notice black, tarry stools—especially when accompanied by dizziness, vomiting, abdominal pain, or signs of anemia. With timely diagnosis and targeted therapy, most patients recover fully and can adopt preventive strategies to avoid future bleeds.

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References:

• Mayo Clinic. “Melena.” Accessed May 2026. https://www.mayoclinic.org
• Cleveland Clinic. “Upper Gastrointestinal Bleeding.” Updated 2024. https://my.clevelandclinic.org
• American College of Gastroenterology. “Management of Patients with Peptic Ulcer Bleeding.” 2023 guideline. https://gi.org
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Bleeding in the Digestive Tract.” 2022. https://www.niddk.nih.gov
• World Health Organization. “Guidelines for the management of variceal hemorrhage.” 2021. https://www.who.int

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