Gangrene << GANG green >> is the death of body tissues from lack of oxygen. It is caused by a loss of blood supply to areas of the body, often the hands or feet.
A gradual loss of blood supply causes dry gangrene. This is often the result of diabetes, arteriosclerosis, or severe frostbite. The involved area becomes painful and cold. Later, the skin darkens. Eventually, the dead tissue dries up and drops off. It does not become infected, and complete healing usually occurs at the junction between living and dead tissue. Therefore, dry gangrene does not threaten a person’s life.
A far more serious condition, called moist gangrene, results from a sudden loss of blood supply. This may follow a crushing injury, a bad burn, or a clot that blocks an artery. The resulting tissue death is irregular, with some cells surviving longer than others. Injured but still living cells leak fluids, making the affected tissues moist. Bacteria flourish in this moist environment. At first, the skin becomes swollen and may develop blisters. As the gangrene proceeds, the area becomes foul-smelling. The infection spreads to other parts of the body, and may be fatal.
A form of gangrene called gas gangrene is particularly deadly. It occurs in wounds infected by bacteria that thrive in a low-oxygen environment. The bacteria release gas and poisons. Gas gangrene causes high fever, brownish pus, and gas bubbles beneath the skin. The poisons spread quickly, leading to death in days if the person is not treated.
Doctors treat gangrene by improving the blood flow and supply of oxygen to the affected area. Surgery may be necessary to remove or to by-pass an obstruction in a large artery. Drugs that improve blood flow through smaller arteries may be helpful. Other drugs may be given to combat bacterial infections. In some cases of gas gangrene, the affected limb is put in a pressurized oxygen chamber to prevent the growth of anaerobic bacteria. When other treatments fail, dead tissue must be removed surgically.
