Gangrene is the death and decay of body tissue. There are several kinds of gangrene. The most common kind, called dry gangrene, occurs in the extremities of the body when the supply of blood to a tissue is cut off. As a result, cells in the tissue cannot receive adequate nutrients and cannot get rid of their waste products. The affected area turns dark, then blackens, and slowly dries up and becomes shriveled. It is eventually separated from the healthy surrounding tissue by a sharp line of demarcation, after which the dried-up tissue falls or sloughs off. The most frequent causes of dry gangrene are obstruction of a blood vessel, usually by a clot, and hardening of the arteries, especially in old people and diabetics. It may also occur after fingers or toes have been badly frostbitten and frozen.
Moist gangrene can affect any tissue in the body. It is caused by certain kinds of bacteria that produce toxins, or poisons, destructive to tissue. There is a foul-smelling watery discharge in the affected area. Another kind of gangrene, called gas gangrene, is also caused by bacteria. The bacteria, which usually infect deep wounds, produce gases that collect in the tissue.
Gangrene is very serious. Moist gangrene and gas gangrene require prompt treatment. The affected tissue must often be surgically removed to prevent the spread of gangrene to healthy tissue. Antibiotic treatment is sometimes helpful. Dry gangrene does not require emergency surgical treatment. Instead, the physician tries to keep the gangrene from spreading by dilating the blood vessels to improve circulation or by removing obstructions from the vessels. After this the process is allowed to run its natural course until demarcation and sloughing off occur.