Black Stool (Melena): Causes, Symptoms, and When It's Dangerous

What is Black Stool (Melena)?

The three most common reasons for passing black stool are:

• Consumption of liquorice or foods that darken stool
• Iron supplements or bismuth-containing medications (such as Pepto-Bismol)
• Melena: black stool resulting from gastrointestinal bleeding

The term melena derives from the Greek word mélaina, meaning “black”. It refers specifically to the passage of black, shiny, tar-like, foul-smelling stool caused by acute intestinal bleeding originating above the ligament of Treitz (the duodenojejunal flexure, the anatomical boundary between the upper and lower gastrointestinal tract).

Understanding Upper Gastrointestinal Bleeding

Upper gastrointestinal (GI) bleeds account for approximately 90% of all gastrointestinal hemorrhages. They can originate from any of the following structures:

• The oropharyngeal cavity (mouth and throat)
• The esophagus
• The stomach
• The first portion of the duodenum

The distinctive black color of melenic stool is caused by the action of gastric acids and digestive enzymes on the hemoglobin contained in red blood cells. As blood passes through the stomach, hemoglobin, normally bright red, is broken down into a dark, oxidized compound called hematin. This gives the stool its characteristic black, tarry appearance and pungent odor.

As little as 50 mL of blood entering the stomach is sufficient to produce this transformation and cause visibly darkened stool. To put that in perspective, 50 mL is roughly equivalent to three and a half tablespoons, a relatively small amount of blood that can have a dramatic visual impact.

Why Melena Is a Medical Emergency

Melena is an indicator of recent or ongoing gastrointestinal bleeding and must be treated as a potential emergency until proven otherwise. The bleeding source could be actively hemorrhaging, dormant, or may have recently stopped. However, identifying the cause remains urgent.

Gastrointestinal hemorrhages are clinically classified into three activity types:

• Type I: Active bleeding: Ongoing hemorrhage is visible at the time of investigation
• Type II: Inactive bleeding: Evidence of recent bleeding, such as an adherent clot or visible vessel, but no active bleeding at the time of endoscopy
• Type III: Past bleeding: Healed or resolved bleeding, with no current signs of active hemorrhage or imminent re-bleeding

It is worth noting that while melena almost always indicates an upper GI source, the lower digestive tract (including the jejunum, ileum, cecum, colon, and rectum) can occasionally produce melena as well. This is particularly true when intestinal transit slows, giving hemoglobin enough time to be fully metabolized and absorbed before the stool is passed.

Most Serious Complications

The most dangerous potential consequences of gastrointestinal bleeding include:

• Hypovolemic shock: A life-threatening drop in circulating blood volume
• Tissue hypoxemia/hypoxia: Inadequate oxygen delivery to vital organs
• Death, if the hemorrhage is massive and not promptly treated

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Causes of Black Stool and Melena

The causes of melena are essentially the causes of upper gastrointestinal bleeding. The following are the most clinically relevant:

1. Peptic Ulcer Disease

Peptic ulcers are the single most common cause of upper GI bleeding, accounting for approximately 40–50% of cases. A peptic ulcer is a break in the mucosal lining of the stomach (gastric ulcer) or the duodenum (duodenal ulcer), exposing the underlying tissue to the corrosive effects of stomach acid.

The main causes of peptic ulcers include:

• Helicobacter pylori infection: A gram-negative bacterium that colonizes the gastric mucosa and disrupts its protective mechanisms. H. pylori is found in the majority of patients with duodenal ulcers.
• Non-steroidal anti-inflammatory drugs (NSAIDs): Anti-inflammatory medications such as ibuprofen, naproxen, and aspirin inhibit prostaglandin synthesis, which impairs the mucosal protective barrier and increases vulnerability to acid damage. This risk is significantly amplified in elderly patients and those using high doses over prolonged periods.
• Excessive gastric acid secretion: Conditions such as Zollinger-Ellison syndrome (a rare gastrin-secreting tumor) can cause extreme overproduction of stomach acid.

Peptic ulcers bleed when the ulcer erodes into a blood vessel in the underlying submucosa or muscularis propria. When a major vessel such as the gastroduodenal artery is eroded, the resulting hemorrhage can be life-threatening.

2. Mallory-Weiss Syndrome

The Mallory-Weiss syndrome involves a longitudinal tear, or laceration, in the mucosa at the gastroesophageal junction. This is the area where the esophagus connects to the stomach. This typically occurs as a result of:

• Severe, repeated vomiting or retching
• Alcohol abuse (which predisposes to vomiting and weakens mucosal integrity)
• Other causes of sudden increases in intra-abdominal pressure, such as severe coughing, seizures, or hiccuping

The mucosal tear bleeds into the stomach, causing hematemesis (vomiting blood) and/or melena. While most Mallory-Weiss tears stop bleeding spontaneously, some require endoscopic treatment.

3. Gastroesophageal Varices and Congestive Gastropathy

Gastroesophageal varices are dilated, tortuous veins in the walls of the esophagus and/or stomach, caused by increased pressure in the portal venous system (portal hypertension).

Portal hypertension is most commonly caused by liver cirrhosis, though it can also result from other conditions such as portal vein thrombosis or hepatic vein obstruction (Budd-Chiari syndrome).

As portal pressure rises, blood is rerouted through alternative venous pathways, causing veins in the esophagus and stomach to dilate and become fragile. When these variceal vessels rupture, the resulting hemorrhage is often massive, rapid, and life-threatening.

Key facts about variceal bleeding:

• Occurs in approximately 25–35% of patients with cirrhosis at some point
• Carries a 6-week mortality rate of approximately 15–20%, even with modern treatment
• High risk of re-bleeding within the first weeks if not preventively treated
• Congestive (portal hypertensive) gastropathy, which involves diffuse mucosal changes in the stomach due to portal hypertension, can also contribute to chronic blood loss and melena

4. Esophagitis and Gastritis

Esophagitis (inflammation of the esophageal lining) and gastritis (inflammation of the gastric mucosa) are common causes of upper GI bleeding, particularly in patients with:

• Gastroesophageal reflux disease (GERD): Chronic reflux of stomach acid into the esophagus damages the mucosal lining, causing erosive esophagitis that can bleed.
• Stress-related mucosal disease: Critically ill patients (particularly those in intensive care units) are at significant risk of developing acute erosive gastritis and stress ulcers.
• Chemical or drug-induced gastritis: Alcohol, NSAIDs, and certain other medications can directly damage the gastric mucosa.

While esophagitis and gastritis are less likely to cause massive bleeding than peptic ulcers or varices, they are important and common sources of slow, ongoing blood loss that can lead to significant anemia over time.

5. Gastrointestinal Tumors

Gastrointestinal tumors, such as gastric cancer, esophageal cancer, gastrointestinal stromal tumors (GISTs), and ampullary tumors, can ulcerate and erode into blood vessels. This process may lead to chronic or acute bleeding.

Tumor-related bleeding may present as:

• Slow, chronic blood loss leading to iron-deficiency anemia
• Acute hemorrhage with hematemesis or melena

Unexplained iron-deficiency anemia or melena in an older adult should always prompt investigation to exclude malignancy.

6. Other Causes

Less common but clinically significant causes of upper GI bleeding include:

• Dieulafoy’s lesion: An abnormally large submucosal artery that erodes through the overlying mucosa without forming an ulcer. This condition can cause massive, recurrent bleeding that is often difficult to diagnose
• Hemobilia: Bleeding into the biliary tract, usually following trauma or hepatic artery aneurysm
• Aortoenteric fistula: An abnormal connection between the aorta and the intestinal lumen. This condition is rare but potentially catastrophic, particularly in patients with previous aortic surgery
• Coagulation disorders: Including hemophilia, thrombocytopenia, or anticoagulant therapy (e.g., warfarin, heparin, direct oral anticoagulants)

Difference Between Melena and Hematochezia

Understanding the distinction between these two terms is fundamental in gastroenterology, as they point to different bleeding sources and carry different clinical implications.

Hematochezia refers to the passage of bright red or maroon-colored blood mixed with or coating the stool. It typically indicates bleeding from the lower gastrointestinal tract, most commonly the colon or rectum. Common causes include:

• Diverticulitis: Inflammation and potential perforation of colonic diverticula. This condition is the most common cause of significant lower GI bleeding in adults over 50
• Arteriovenous malformations (AVMs): Fragile, abnormal blood vessel connections in the colon wall that can rupture and bleed
• Colorectal neoplasms: Colon cancer or large polyps that erode into blood vessels
• Ischemic colitis: Reduced blood flow to the colon causing mucosal ischemia and bleeding
• Hemorrhoids and anal fissures: Very common causes of minor bright red rectal bleeding, usually coating the stool or visible on toilet paper

The key clinical distinction:

Important exceptions:

• A massive upper GI bleed with very rapid intestinal transit may not allow sufficient time for hemoglobin digestion, resulting in bright red stool (hematochezia) despite the upper GI origin. This scenario indicates a particularly severe hemorrhage.
• Conversely, a slow lower GI bleed with prolonged intestinal transit time can allow hemoglobin to be fully oxidized and digested, resulting in melena despite a lower GI source.

This overlap underscores the importance of endoscopic evaluation rather than relying solely on stool color to determine the bleeding source.

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Symptoms

The symptoms of gastrointestinal bleeding become clinically evident when approximately more than 15% of total blood volume has been lost. At this threshold, the body’s compensatory mechanisms start to fail. These mechanisms include an increased heart rate, vasoconstriction, and the redistribution of blood flow. The system can no longer keep up with the demand.

Early and Moderate Symptoms

• Anemia, which manifests as:
  • Pale skin and mucous membranes
  • Dizziness and vertigo
  • Fatigue and weakness
  • Reduced exercise tolerance
• Chest pain (due to reduced oxygen delivery to the myocardium)
• Abdominal pain or discomfort
• Tachycardia: Increased heart rate as the body attempts to compensate for reduced blood volume
• Hypotension: Low blood pressure, which may worsen on standing (orthostatic hypotension)
• Excessive thirst: A response to reduced circulating volume
• Dyspnea: Shortness of breath due to reduced oxygen-carrying capacity
• Syncope (fainting): Loss of consciousness due to inadequate cerebral perfusion
• Hematemesis: Vomiting blood (bright red or “coffee-ground” material, the latter indicating digested blood)

Severe Symptoms (After Loss of 40–50% of Blood Volume)

When more than 40 to 50% of total blood volume is lost, or when hemorrhage is not promptly controlled and blood volume is not restored, critical systemic deterioration occurs. The body’s compensatory mechanisms fail, and vital organs begin to suffer from inadequate perfusion:

• Hypovolemic shock: A life-threatening circulatory collapse characterized by severe hypotension, rapid weak pulse, cold clammy skin, and altered mental status (confusion, agitation, or loss of consciousness)
• Tissue hypoxia: Insufficient oxygen delivery to cells throughout the body, including the heart, brain, kidneys, and liver
• Lactic acidosis: Accumulation of lactic acid in the blood, which occurs when cells switch to anaerobic metabolism due to inadequate oxygen. This serves as a marker of severe shock and tissue ischemia
• Multi-organ dysfunction syndrome (MODS): Progressive failure of multiple organ systems (renal failure, hepatic failure, respiratory failure, coagulopathy)
• Death

Symptoms Related to the Underlying Cause

In addition to the symptoms of blood loss itself, patients with melena often present with symptoms specific to the underlying condition causing the bleed. For example:

• Patients with peptic ulcer disease may report burning epigastric pain, often relieved by eating (duodenal ulcers) or worsened by food (gastric ulcers)
• Patients with liver cirrhosis and portal hypertension may show jaundice, ascites, spider angiomas, palmar erythema, and peripheral edema
• Patients with esophagitis or GERD may describe chronic heartburn, acid regurgitation, and dysphagia
• Patients with gastric or esophageal cancer may report unintentional weight loss, progressive dysphagia, and early satiety

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Diagnosis

The diagnosis of melena and its underlying cause involves a combination of clinical assessment, laboratory investigations, and instrumental (endoscopic and imaging) studies. The goal is to identify the bleeding source accurately and promptly. This allows appropriate treatment to begin, ideally during the same diagnostic procedure.

In rare cases of severe, uncontrolled hemorrhage, emergency surgery may be required before a complete diagnostic workup can be performed.

1. Clinical Diagnosis

The initial assessment is based on:

• Stool characteristics: Black, sticky, tarry, shiny stool with a characteristic foul odor is highly suggestive of melena. A digital rectal examination can confirm stool color and consistency.
• Symptoms of hypovolemia: Hypotension (especially postural), diaphoresis (sweating), tachycardia, pallor, and syncope all indicate significant blood loss.
• Medical history: The clinician will carefully ask about:
  • Previous episodes of GI bleeding
  • History of peptic ulcers, liver disease, or inflammatory bowel disease
  • Use of NSAIDs, anticoagulants, or antiplatelet agents
  • Alcohol consumption
  • Recent severe vomiting (suggesting Mallory-Weiss tear)
  • Symptoms of esophagitis, gastritis, or GERD
  • Family history of GI malignancy

2. Laboratory Investigations

Blood tests are essential to assess the severity of blood loss and investigate the underlying cause:

• Complete blood count (CBC) with platelet count: Hemoglobin and hematocrit levels indicate the degree of anemia; platelet count is relevant for coagulation assessment
• Blood urea nitrogen (BUN) and creatinine: A disproportionate rise in BUN relative to creatinine (elevated BUN:creatinine ratio) is a classic marker of upper GI bleeding, as digested blood proteins are absorbed in the small intestine and metabolized to urea
• Liver function tests (LFTs): To assess for hepatic disease and portal hypertension
• Coagulation studies: Prothrombin time (PT/INR), activated partial thromboplastin time (aPTT), and fibrinogen are particularly important in patients on anticoagulants or with liver disease
• Blood type and crossmatch: Essential if blood transfusion is anticipated
• Tumor markers: AFP, CEA, CA19-9 in cases where malignancy is suspected
• H. pylori testing: Serology, stool antigen test, or urea breath test to detect Helicobacter pylori infection
• Hepatitis serology: In patients with suspected viral hepatitis-related cirrhosis

3. Instrumental (Procedural) Diagnosis

A range of diagnostic procedures may be employed depending on the clinical presentation, suspected bleeding source, and severity of hemorrhage:

Nasogastric Tube Aspiration

A flexible tube is passed through the nose and advanced into the stomach. The aspirated content can confirm an upper GI source if it contains blood or “coffee-ground” material. A clear, bile-stained aspirate makes an active upper GI bleed less likely but does not exclude it entirely. This procedure is less commonly used in modern practice as it has been largely superseded by early endoscopy.

Esophagogastroduodenoscopy (EGD / Upper Endoscopy / Gastroscopy)

EGD (gastroscopy) is the gold standard for both diagnosing and treating upper gastrointestinal bleeding. A flexible endoscope equipped with a camera and light source is passed through the mouth, down the esophagus, into the stomach, and into the duodenum.

EGD allows the physician to:

• Directly visualize the bleeding source
• Characterize the lesion (e.g., Forrest classification of peptic ulcers, which guides re-bleeding risk stratification)
• Apply endoscopic hemostasis (e.g., injection therapy, thermal coagulation, mechanical clips, band ligation for varices)

Early endoscopy within 24 hours of presentation is recommended by international guidelines for most patients with upper GI bleeding. High-risk patients (those with hemodynamic instability, signs of active hemorrhage, or cirrhosis) should undergo urgent endoscopy within 12 hours.

Colonoscopy and Rectoscopy

Colonoscopy (examination of the entire colon) and rectoscopy (examination of the rectum) are the preferred investigations when a lower GI bleeding source is suspected. They are particularly useful for diagnosing:

• Bleeding from hemorrhoids
• Rectal and colonic lesions
• Inflammatory bowel disease
• Colonic diverticula or AVMs
• Colorectal tumors

Colonoscopy also allows for simultaneous therapeutic intervention (e.g., polypectomy, AVM cauterization, hemostatic clip placement).

Capsule Endoscopy

A small camera capsule, which the patient swallows, provides images of the small intestine. This region cannot be accessed by standard upper or lower endoscopy. It is particularly useful in cases of obscure GI bleeding (persistent or recurrent bleeding with no source identified by EGD or colonoscopy), where a small bowel source (such as an AVM or Meckel’s diverticulum) is suspected.

Angiography (Mesenteric Arteriography)

Angiography involves injecting contrast dye into the mesenteric arteries and capturing X-ray images to identify the bleeding source. It is particularly useful when:

• Bleeding is active and rapid (requires a bleeding rate of at least 0.5–1 mL/min to be detectable)
• Endoscopy has failed to localize the source
• The patient is too unstable for endoscopy

Angiography can also be therapeutic, allowing embolization to block the bleeding vessel as an alternative to surgery.

CT Angiography (CTA)

CT scanning with intravenous contrast (CT angiography) is increasingly used as a first-line imaging modality in patients with significant GI bleeding. It can rapidly identify the bleeding source (with a sensitivity of approximately 85–90% for active bleeds) and guide subsequent endoscopic or surgical management.

CT angiography is particularly valuable in:

• Patients who are hemodynamically unstable
• Cases of obscure GI bleeding
• Surgical planning

Radionuclide Scintigraphy (Tagged Red Blood Cell Scan)

A small amount of the patient’s red blood cells is labeled with a radioactive tracer and re-injected. A gamma camera then tracks where the labeled cells accumulate, indicating the bleeding site. This technique can detect very slow bleeds (as low as 0.1 mL/min) and is most useful for intermittent or slow lower GI bleeding.

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Prognosis and Complications

The outlook for patients with melena varies considerably depending on the severity of the bleeding episode, the underlying cause, and the presence of comorbid conditions.

Overall Prognosis

In the majority of patients, gastrointestinal bleeding stops spontaneously without the need for invasive intervention. However, all patients with melena require careful monitoring. This includes both the acute episode and long-term follow-up to detect and manage any recurrence.

Following discharge, patients must be educated to recognize the signs of re-bleeding (return of black stool, rectal bleeding, vomiting blood, dizziness, or collapse) and instructed to seek immediate medical attention if these symptoms recur.

Mortality

The overall in-hospital mortality rate for upper GI bleeding is approximately 8–10%, though this figure has declined significantly over recent decades thanks to advances in endoscopic therapy, intensive care, and risk stratification.

However, mortality risk is substantially higher in patients with certain comorbidities that impair the body’s ability to compensate for blood loss or that complicate treatment:

• Coagulation disorders: Including liver disease-related coagulopathy, thrombocytopenia, or anticoagulant therapy
• Chronic kidney disease or acute renal failure: Impairs platelet function and is associated with worse outcomes
• Cardiac failure: Limits the heart’s capacity to compensate for volume loss
• Liver cirrhosis: Associated with coagulopathy, thrombocytopenia, impaired immune function, and portal hypertension. These complications dramatically increase the risk of re-bleeding and mortality
• Portal hypertension: Variceal bleeding in particular carries a high re-bleeding risk and mortality
• Malignancy: Active cancer is an independent predictor of poor outcome in GI bleeding
• Advanced age: Elderly patients have reduced physiological reserve and higher rates of comorbid disease

Risk Stratification

Several validated clinical scoring systems are used to stratify patients according to their risk of re-bleeding and death, including:

• Glasgow-Blatchford Score (GBS): Incorporates blood urea, hemoglobin, systolic blood pressure, pulse rate, and clinical features. High scores predict the need for intervention.
• Rockall Score: Assessed before and after endoscopy, incorporating age, hemodynamic status, comorbidities, endoscopic diagnosis, and stigmata of recent hemorrhage.
• AIMS65 Score: This score incorporates albumin, INR, mental status, systolic blood pressure, and age. It is a simpler tool validated in multiple settings.

These scores help clinicians decide on the appropriate level of care, timing of endoscopy, and need for ICU admission.

Potential Complications

Massive or inadequately treated gastrointestinal hemorrhage can lead to:

• Hypovolemic shock: Severe, potentially irreversible circulatory collapse
• Acute kidney injury (AKI): Due to reduced renal perfusion
• Myocardial ischemia or infarction: Due to reduced coronary perfusion in patients with pre-existing coronary artery disease
• Aspiration pneumonia: Particularly if the patient vomits blood and aspirates into the airways
• Multi-organ failure
• Death

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Treatment

The management of melena and upper GI bleeding is guided by the severity of the hemorrhage, the location and nature of the bleeding source, and the presence of associated conditions. Treatment often begins at the same time as diagnosis, especially during endoscopy.

In many patients, bleeding stops spontaneously. However, when it does not, immediate and coordinated intervention is required.

Initial Resuscitation and Stabilization

Regardless of the underlying cause, the first priority is always hemodynamic stabilization:

1. Establish intravenous access: Two large-bore peripheral IV lines should be placed immediately
2. Fluid resuscitation: Intravenous crystalloid fluids (normal saline or Ringer’s lactate) are administered to restore circulating volume
3. Blood transfusion: Packed red blood cells are transfused to restore hemoglobin. Current evidence supports a restrictive transfusion threshold (hemoglobin < 7 g/dL in most patients; < 8 g/dL in patients with ischemic heart disease), as over-transfusion can worsen portal hypertension and increase re-bleeding risk in cirrhotic patients
4. Fresh frozen plasma (FFP) and platelets: Administered when coagulopathy or thrombocytopenia is present
5. Oxygen supplementation: To maintain adequate tissue oxygenation
6. Airway protection: Endotracheal intubation may be necessary in patients with altered consciousness, massive hematemesis, or severe encephalopathy to prevent aspiration
7. Urinary catheter: To monitor urine output as a marker of organ perfusion

Localization of the Bleeding Source

Identifying the precise source of bleeding is essential for targeted treatment. As described in the Diagnosis section, upper GI endoscopy (EGD) performed within 24 hours (or urgently in high-risk patients) is the cornerstone of both diagnosis and treatment.

Specific Treatment Approaches

Reducing Gastric Acidity

• Proton pump inhibitors (PPIs): High-dose intravenous PPIs (e.g., pantoprazole or omeprazole) are the cornerstone of pharmacological treatment for peptic ulcer bleeding. By suppressing acid secretion, they promote clot stability at the ulcer site and reduce re-bleeding risk. Current guidelines recommend high-dose IV PPI infusion (80 mg bolus followed by 8 mg/hour continuous infusion) for 72 hours in patients with high-risk peptic ulcer stigmata.
• H2-receptor antagonists: Less potent than PPIs; rarely used as first-line therapy in acute GI bleeding.

Endoscopic Hemostasis

Endoscopy allows direct treatment of the bleeding source using several techniques:

• Injection therapy: Epinephrine (adrenaline) is injected around the bleeding vessel to cause vasoconstriction and tamponade. Often combined with another modality.
• Thermal coagulation: Heat energy (bipolar electrocoagulation, heater probe, or argon plasma coagulation) is applied to the bleeding vessel to seal it.
• Mechanical hemostasis: Hemostatic clips, also called endoclips, are used to clamp the bleeding vessel. This method works especially well for actively bleeding ulcers.
• Variceal band ligation (EVL): For esophageal varices, small rubber bands are applied to ligate the varices, cutting off their blood supply. This is currently the preferred endoscopic treatment for variceal bleeding.
• Variceal sclerotherapy: Injection of sclerosing agents into or around varices. This method is now less commonly used than band ligation.
• Over-the-scope clip (OTSC): A larger, more powerful clipping device used for refractory bleeding from ulcers or Dieulafoy’s lesions.

Treatment of Variceal Bleeding and Portal Hypertension

Variceal bleeding requires specific additional management:

• Vasoactive drugs: Medications that reduce portal pressure by constricting the splanchnic circulation are started as soon as variceal bleeding is suspected, ideally before endoscopy:
  • Terlipressin (vasopressin analogue): The only drug proven to reduce mortality in variceal bleeding
  • Somatostatin and analogues (octreotide, vapreotide): Widely used; reduce portal pressure and splanchnic blood flow
• Antibiotic prophylaxis: Patients with cirrhosis and GI bleeding are at high risk of bacterial infections (particularly spontaneous bacterial peritonitis). A short course of antibiotics (typically norfloxacin or ceftriaxone) is recommended for all cirrhotic patients with GI bleeding.
• Balloon tamponade (Sengstaken-Blakemore tube): A balloon-tipped tube passed through the mouth or nose and inflated in the esophagus and/or stomach to physically compress bleeding varices. Used only as a bridge to definitive treatment in massive, uncontrolled variceal hemorrhage.
• Transjugular intrahepatic portosystemic shunt (TIPS): A minimally invasive radiological procedure that creates a channel between the portal vein and hepatic vein within the liver, bypassing the high-resistance cirrhotic liver tissue and reducing portal pressure. TIPS is used in patients with refractory variceal bleeding or those at high risk of treatment failure.

H. pylori Eradication

If H. pylori infection is confirmed as a contributing factor to peptic ulcer bleeding, eradication therapy (a combination of antibiotics and a PPI, typically given for 7–14 days) is essential to reduce the risk of ulcer recurrence and re-bleeding.

Reversal of Anticoagulation

In patients on anticoagulant therapy (warfarin, direct oral anticoagulants) who present with significant GI bleeding, anticoagulation may need to be temporarily reversed or held:

• Warfarin: Reversed with intravenous vitamin K ± fresh frozen plasma or four-factor prothrombin complex concentrate (PCC)
• Direct oral anticoagulants (DOACs): Specific reversal agents include idarucizumab (for dabigatran) and andexanet alfa (for factor Xa inhibitors)

The decision to reverse anticoagulation must weigh the risk of ongoing hemorrhage against the risk of thromboembolic complications (e.g., stroke in patients with atrial fibrillation or mechanical heart valves).

Interventional Radiology (Angioembolization)

When endoscopic treatment fails to control bleeding, percutaneous transcatheter arterial embolization by an interventional radiologist is an effective alternative to surgery. A catheter is advanced into the mesenteric arterial system under fluoroscopic guidance, and the bleeding vessel is blocked using coils, gelatin sponge, or other embolic agents.

Surgical Treatment

Surgery is reserved for refractory cases in which endoscopic and radiological measures have failed, or in the setting of a surgical emergency (e.g., perforated ulcer). Surgical options include:

• Oversewing of the bleeding vessel (for ulcer hemorrhage)
• Partial or total gastrectomy (for massive or recurrent gastric bleeding)
• Surgical portosystemic shunts (for refractory portal hypertension)
• Emergency bowel resection (for lower GI bleeding sources such as colonic angiodysplasia or diverticular hemorrhage unresponsive to other treatment)

Long-Term Management of the Underlying Condition

Successfully stopping an acute bleed is only one part of the treatment. Long-term management of the underlying disease is equally important to prevent recurrence:

• Peptic ulcer disease: H. pylori eradication; avoidance of NSAIDs; long-term PPI therapy if NSAIDs cannot be discontinued; lifestyle modifications (alcohol reduction, smoking cessation)
• Liver cirrhosis and portal hypertension: Non-selective beta-blockers (propranolol or carvedilol) to reduce portal pressure and prevent variceal re-bleeding; regular surveillance endoscopy; treatment of the underlying cause of cirrhosis (e.g., antiviral therapy for hepatitis B or C)
• Gastrointestinal malignancy: Oncological management (surgery, chemotherapy, radiotherapy) as appropriate
• Coagulation disorders: Optimization of anticoagulant therapy; hematological management

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Key Takeaways

• Black, tarry stool (melena) is a sign of upper gastrointestinal bleeding until proven otherwise, and should always be investigated promptly.
• Common benign causes of dark stool, like iron supplements or liquorice, must be distinguished from true melena through clinical evaluation.
• The most common cause of melena is peptic ulcer disease, followed by esophageal/gastric varices, Mallory-Weiss tears, and esophagogastritis.
• Symptoms of blood loss, such as pallor, dizziness, tachycardia, and hypotension, indicate significant hemorrhage and require urgent medical attention.
• Upper GI endoscopy within 24 hours (or urgently in high-risk patients) is both the diagnostic and therapeutic gold standard.
• Mortality is approximately 8–10% overall, but is significantly higher in patients with liver disease, coagulopathy, malignancy, or advanced age.
• Early medical attention is critical. Do not ignore black or tarry stools, particularly if they occur alongside any systemic symptoms.

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References and Bibliography

• Hahn JM. Checklist Medicina Interna, 6th edition. CIC Ed. Internazionale.
• Mayo Clinic: Gastrointestinal Bleeding – Symptoms and Causes
• National Centre for Biotechnology Information (NCBI): Gastrointestinal Bleeding
• Laine L, Barkun AN, Saltzman JR, et al. ACG Clinical Guideline: Upper Gastrointestinal and Ulcer Bleeding. American Journal of Gastroenterology. 2021;116(5):899–917.
• Gralnek IM, Stanley AJ, Morris AJ, et al. Endoscopic diagnosis and management of nonvariceal upper gastrointestinal hemorrhage (NVUGIH): European Society of Gastrointestinal Endoscopy (ESGE) Guideline – Update 2021. Endoscopy. 2021;53(3):300–332.
• de Franchis R, Bosch J, Garcia-Tsao G, et al. Baveno VII: Renewing consensus in portal hypertension. Journal of Hepatology. 2022;76(4):959–974.
• Sung JJY, Chiu PWY, Chan FKL, et al. Asia-Pacific working group consensus on non-variceal upper gastrointestinal bleeding: an update 2018. Gut. 2018;67(10):1757–1768.
• Blatchford O, Murray WR, Blatchford M. A risk score to predict need for treatment for upper-gastrointestinal haemorrhage. The Lancet. 2000;356(9238):1318–1321.
• Rockall TA, Logan RF, Devlin HB, Northfield TC. Risk assessment after acute upper gastrointestinal haemorrhage. Gut. 1996;38(3):316–321.