A14. Gangrenes

Gangrene is the term for infarction of the extremities (although gangrene is also used to describe haemorrhagic infarct of the GI tract). There are two types, dry and wet gangrene.

Dry gangrene

Dry gangrene occurs when the extremities (mainly the toes and feet) receive inadequate blood flow. This occurs mostly due to atherosclerosis (called peripheral artery disease) or uncontrolled diabetes mellitus, or a combination of both. The affected tissue becomes cold, loses its normal color, becoming darker and darker until it becomes completely black and falls off completely if not treated.

Wet gangrene

Wet gangrene occurs when there is a saprophytic superinfection on top of the dry gangrene, which causes the tissue to rot. Saprophytic pathogens are bacteria and fungi that thrive in dead tissue. The result is the formation of pus, often foul-smelling. Wet gangrene can also occur in the lung and the intestine.

Gas gangrene

Gas gangrene may be regarded as a third type, although it’s not a pathological entity on its own. Gas gangrene refers to the wet gangrene caused by the bacterium clostridium perfringens, which produces gas, resulting in the formation of bubbles in the soft tissue.

Treatment

The treatment of gangrene is surgical removal, as the necrotic tissue must be removed. In cases of wet gangrene, antibiotic therapy is also necessary.