Melena or melaena refers to the dark black, tarry feces that are associated with upper gastrointestinal bleeding. The black color and characteristic strong odor are caused by hemoglobin in the blood being altered by digestive enzymes and intestinal bacteria.Iron supplements may cause a grayish-black stool that should be distinguished from melena, as should black coloration caused by a number of medications, such as bismuth subsalicylate (the active ingredient in Pepto-Bismol), or by foods such as beetroot, black liquorice, or blueberries. Causes
The most common cause of melena is peptic ulcer disease. However, any bleeding within the upper gastrointestinal tract or the ascending colon can lead to melena. Melena may also be a complication of anticoagulant medications, such as warfarin.Causes of upper gastrointestinal bleeding that may result in melena include malignant tumors affecting the esophagus, stomach or small intestine, hemorrhagic blood diseases, such as thrombocytopenia and hemophilia, gastritis, Stomach cancer, esophageal varices, Meckels diverticulum and Mallory-Weiss syndrome.Causes of "false" melena include iron supplements, Pepto-Bismol, Maalox, and lead, blood swallowed as a result of a nose bleed (epistaxis), and blood ingested as part of the diet, as with consumption of black pudding (blood sausage), or with the traditional African Maasai diet, which includes much blood drained from cattle.Melena is considered a medical emergency as it arises from a significant amount of bleeding. Urgent care is required to rule out serious causes and prevent potentially life-threatening emergencies.A less serious, self-limiting case of melena can occur in newborns two to three days after delivery, due to swallowed maternal blood.
For most people there exists a balance between the host defenses and the oral micriobiota but if the host defenses are compromised like during minor illness such as influenza or an upper respiratory tract infection, pericoronitis results. Another common cause is entrapment of food beneath the gum flap (also called an operculum). Pericoronitis can present as a mild infection or severe infection. In its mildest form it is just a localized tissue swelling and soreness whereas in severe forms the swelling is slightly larger even sometimes creating trismus (difficulty opening the mouth). Occasionally, an impacted tooth causes sufficient pressure on the roots of adjacent teeth causing it to resorb. An impacted tooth occupies space that is usually filled with bone. This weakens that area of bone and renders the jaw more susceptible to fracture. When impacted teeth are retained completely within the alveolar process, the associated follicular sac is also retained along with it. Though in most persons the dental follicle maintains its original size sometimes it may undergo cystic degeneration and become a dentigerous cyst or a keratocyst. Symptoms
Most commonly the individual complains of food getting lodged beneath the gums and a soreness that is usually confused with throat infections. In slightly milder forms a swelling is visible and mouth opening becomes difficult in severe cases. Pain is invariably present. Management
Impacted teeth might be extracted or left alone, depending on the dentist (and the health authoritys guidelines in that country) and the situation.