Melena overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
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.
Historical Perspective
Classification
Pathophysiology
Melena, is stool with blood, that has been altered by the gut flora, and appears black/"tarry".
Causes
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.