Melena

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Melena or melaena refers to the black, “tarry” feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon.

Melena, is stool with blood, that has been altered by the gut flora, and appears black/”tarry“.

The most common cause of melena is peptic ulcer disease. Any other cause of bleeding from the upper gastro-intestinal tract, or even the ascending colon, can also cause melena. Melena may also be a sign of drug overdose if a patient is taking anti-coagulants, such as warfarin. A less serious, self-limiting case of melena can occur in newborns two to three days after delivery, due to swallowed maternal blood.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

• Melena is a manifestation of upper gastrointestinal bleeding (UGIB). The term melena is defined as black or tarry stools as a result of blood loss originating proximal to the ligament of Treitz, in the esophagus, stomach, or duodenum.^[1]
• Melena, or black stool, may develop with as little as 50 ml of blood loss from the GI tract per day.^[2]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Melena, is stool with blood, that has been altered by the gut flora, and appears black/”tarry“.

Bleeding originating from the lower GI tract (such as the sigmoid colon and rectum) is generally associated with the passage of bright red blood, or hematochezia, particularly when brisk. Blood acts as a cathartic agent in the intestine, promoting its prompt passage. Only blood that originates from a high source (such as the small intestine), or bleeding from a lower source that occurs slowly enough to allow for oxidation, is associated with melena. For this reason, melena is often associated with hemorrhage in the stomach or duodenum (upper gastrointestinal tract), for example by a peptic ulcer. A rough estimate is that it takes about 14 hours for blood to be broken down within the intestinal lumen; therefore if transit time is less than 14 hours the patient will have hematochezia and if greater than 14 hours the patient will exhibit melena. One often-stated rule of thumb is that melena only occurs if the source of bleeding is above the ligament of Treitz.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ogheneochuko Ajari, MB.BS, MS [2]

The most common cause of melena is peptic ulcer disease. Any other cause of bleeding from the upper gastro-intestinal tract, or even the ascending colon, can also cause melena. Melena may also be a sign of drug overdose if a patient is taking anti-coagulants, such as warfarin. A less serious, self-limiting case of melena can occur in newborns two to three days after delivery, due to swallowed maternal blood.

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Anthrax
• Ebola virus

• Duodenal ulcer
• Esophagitis
• Esophageal varices
• Gastric tumors
• Gastric ulcer
• Gastritis
• Mallory-Weiss syndrome
• Peptic ulcer

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Tayyaba Ali, M.D.[2]

• The annual incidence of hospitalization for acute upper gastrointestinal bleeding (UGIB) in the United States is approximately 65 per 100,000 individuals.^[1]

• The prevalence of melena is almost the same as incidence, as it is a manifestation of an acute condition and is not a chronic disease.

• Overall mortality decreased from 17.1 to 8.2 per 100,000/y which corresponded to a 60.8% decrease after adjustment for age (95% CI, 46.5%-75.1%). The age-standardized mortality rate for ulcer bleeding decreased by 56.5% (95% CI, 41.9%-71.1%).^[2]

• The incidence of upper gastrointestinal bleed increases with age and decreases in people younger than 70 years of age.^[2]

• According to one study done in 2196 patients with upper gastrointestinal bleeding. 620 (28%) were black, 625 (29%) white, 881 (40%) Hispanic, and 70 (3%) were members of other ethnicities.
• In all ethnicities, gastrointestinal ulcer disease is the most common cause of bleeding or melena in patients younger than 35 or older than 65 years. Certain differences in terms of etiology of melena were observed among patients aged 35 to 64 years.
• Blacks aged 50 to 64 years frequently experienced gastroduodenal ulcers, whereas Hispanics aged 35 to 49 years typically had esophageal varices. Rebleeding rates were significantly lower in whites (5.8%) than in Hispanics (9.9%) or blacks (8.7%) (P=0.02).^[3]

• The incidence of UGIB is higher in males than in females (128 versus 65 per 100,000 in one study).^[4]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:

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