The causes of melena can be mild and treatable to severe bleeding in the upper gastrointestinal tract. Some of the probable causes are a bleeding peptic ulcer, gastritis, esophageal varices, gastrointestinal tumor, blood disease, and medicinal side effects, among others.
Melena, also spelled as malaena, is a medical condition related to black or tarry stool. Blood in stool and black-colored feces are not unusual conditions to nearly all of us. While bright-colored blood in stool is caused due to bleeding in the sigmoid colon, rectum, and anal portion, the tarry stool is because of hemorrhage in the upper gastrointestinal tract. Understanding what melena is, and its underlying causes are of paramount importance for people who pass black-colored stool occasionally or frequently.
What Causes Melena?
Medical experts are of the opinion that the color, size, texture, smell, and consistency of feces can tell whether an individual is healthy or not. Considering this, it is apparent that there is something wrong if the person is having an abnormal bowel movement problem, either in terms of frequency or color. Even mild bleeding in the gut (about 50 ml blood) can result in dark-colored stool that signifies melena.
The exact causes of melena are related to hemorrhage in the esophagus, stomach, and small intestine. Thus, in case of melena, the dark coloration of feces is due to oxidation of iron present in hemoglobin, as the blood passes the lower gastrointestinal tract. It is suggested that blood that stays in the digestive tract for 14 hours or more gets oxidized and turns black at the time of expelling in feces.
Bleeding Peptic Ulcer
An underlying peptic ulcer is one of the most common causes. If an ulcer is the causal factor for black stool, the person may manifest other ulceration signs, like heartburn, frequent tendency to vomit, food regurgitation, and an unusual taste in the mouth.
Another causal reason for tarry stool is gastritis or inflammation of the stomach lining. People who have a habit of excessive alcohol consumption and eating spicy foods are at a higher risk of stomach inflammation than others. Also, gastritis related melena is manifested by people who are on steroid drugs for a longer period.
Bleeding in the mouth or nosebleeds also cause melena. What happens in such conditions is that the oozing blood is swallowed knowingly or unknowingly, which is then passed out during defecation. In newborns, melena is resulted due to swallowing of blood from the mother.
Anti-coagulant Side Effect
In some people, melena is caused due to side effects of anti-coagulant drugs. Nevertheless, it does not mean that all people who are on such drugs will show this problem. In short, anti-coagulant overdose or prolonged intake of the same increase the risk for melena.
As the name suggests, esophageal varices refers to dilated blood vessels in the wall of the esophageal portion. Under certain situations, the dilated veins may burst and cause bleeding. Ultimately, the released blood is excreted in an oxidized state during bowel movement.
Other Possible Causes
Presence of tumor in the esophagus, stomach lining, and starting of small intestine may bleed and cause melena. Besides the list above, black or tarry stool can be associated with Mallory-Weiss tear, liver cirrhosis, bowel tumors, giardiasis, and blood diseases.
Very often, people are alarmed with false signs. Like for instance, consuming too many black pudding, chocolates, blueberries and other dark-colored foods will cause black coloration of stool. Also, administering iron supplements alone or in combination with other medications is a reason for asymptomatic melena. So, do not confuse harmless black stool causes with melena.
Diagnosis and Treatment
In order to confirm that blood is causing tarry color in stool, the doctor may conduct stool analysis, gastroscopy, colonoscopy, and other diagnostic tests. If suspected for upper GI disorder, the doctor may perform a GI endoscopy procedure. In some patients, melena is accompanied with low blood pressure levels and anemia, whereas in others, there are no other symptoms, except for black or tarry feces.
The treatment starts with identifying the solid causes of melena. A patient is expected to cooperate the doctor fully, while giving medical history, current medicine intake, lifestyle habits (alcohol intake) and other personal questions. Once the underlying cause of melena is identified, it will be followed with treatment appropriate for the patient. As with any health condition, early diagnosis and timely treatment are the key tips for addressing melena effectively.