Gangrene: Dry, Wet and Gas

Key points

• • Gangrene is death of a large area of tissue (necrosis) from a loss of blood supply, often in a limb, and it may or may not be complicated by infection.
• • Dry gangrene follows a gradual loss of arterial blood without much infection; the part becomes dry, shrunken and black, with a clear line separating it from healthy tissue.
• • Wet gangrene occurs when dead tissue is also invaded by bacteria, so it is moist, swollen, foul-smelling and spreads quickly, and it is far more dangerous.
• • Diabetes and blocked arteries are common settings for gangrene of the foot, combining a poor blood supply with a tendency to infection.
• • Gas gangrene (clostridial myonecrosis) is a rapidly spreading infection caused by Clostridium bacteria that release gas into the tissues, felt as crackling under the skin.
• • Dry gangrene tends to stay put and separate off, while wet and gas gangrene spread and threaten life, so the two behave very differently.