The death and decay of body tissues caused by a reduction or complete loss of blood supply to the area. There are two types: dry and moist. The former is a process of mummification, with the blood supply of the affected area of tissue stopping and the tissue withering up. Moist gangrene is characterised by putrefactive tissue decay caused by bacterial infection. The dead part, when formed of soft tissues, is called a slough and, when part of a bone, is called a sequestrum.
These include injury (especially that sustained in war), disease, FROSTBITE, severe burns, ATHEROMA in large blood vessels, and diseases such as DIABETES MELLITUS and RAYNAUD'S DISEASE. Gas gangrene is a form that occurs when injuries are infected with soil contaminated with gas-producing bacilli such as Clostridium welchii, which are found in well-manured ground.
Dry gangrene must be kept dry, and AMPUTATION of the dead tissue performed when a clear demarcation line with healthy tissue has formed. Wet gangrene requires urgent surgery and prompt use of appropriate antibiotics.