Gangrene

Death of tissue, usually as a result of loss of blood supply. Gangrene may affect a small area of skin or a substantial portion of a limb. Pain is felt in the dying tissues, but once dead they become numb. The affected tissue turns black. There are two types of gangrene: dry and wet. In dry gangrene, there is usually no infection, and the tissue dies because it has no blood supply. Dry gangrene does not spread, and it may be caused by arteriosclerosis, diabetes mellitus, thrombosis, frostbite, or an embolism. Wet gangrene develops when dry gangrene or a wound becomes infected by bacteria. The gangrene spreads and gives off an unpleasant smell. There may be redness, swelling, and oozing pus around the blackened area. A virulent type called gas gangrene is caused by a bacterium that destroys muscles and produces a foulsmelling gas. Treatment of dry gangrene consists of attempting to improve the circulation to the affected area before the tissues die. Antibiotic drugs can prevent wet gangrene from setting in. Amputation of the affected part and the surrounding tissue is necessary.