Melena is a form of digestive bleeding. In most cases, it is a hemorrhage (loss of blood) from the right angle of the colon.

Melena is a form of bleeding from the digestive system. This is then the evacuation of black blood, through the anus.

This type of digestive hemorrhage results in the expulsion of blood, coming from the digestive system: digestive tract, bile ducts or even from the pancreas.

However, melena should not be confused with other digestive hemorrhages and other intestinal complications: coughing up blood, nasal bleeding, gynecological bleeding such as menstruation, etc.

In addition, upper hemorrhages (the origin of which is upstream of the duodenojejunal angle) should be distinguished from low hemorrhages (the origin of which is downstream of this angle). Melena is then a low hemorrhage. and results, in a majority of cases, from hemorrhage from the right angle of the colon.

Different causes can be at the origin of a melena:

• the presence of a polyp (growth of an intestinal mucosa) or cancer
• diverticular bleeding (caused by small hernias formed in the wall of the intestine)
• ischemic, infectious, inflammatory or radiation colitis
• a rectal ulcer (especially in the elderly)
• hemorrhoidal bleeding from hemorrhoids

In rarer cases, melena can find its origin as a result of angiodysplasia, tumors, ulcerations by nonsteroidal anti-inflammatory drugs (NSAIDs).

People suffering from damage to the digestive system are more exposed to the risk of melena (gastric or intestinal ulcer, ischemic colitis, etc.).

The elderly are also more at risk of melena.

The clinical signs of melena are reflected by:

• emission of black blood, accompanied by a foul odor, in the stool
• intestinal pain

The main risk factors for melena correspond to the different possible causes. Either the presence of bleeding in the intestinal system, the presence of ulcers, colitis, etc.

The diagnosis of the disease is confirmed or ruled out following an endoscopy.

The management of the treatment of low bleeding depends on the origin of the latter. It may be a simple therapeutic treatment, an endoscopic ablation or even a particular diet to follow.