Gangrene is a condition in which body tissues decay and eventually die as a result of inadequate blood supply. Although it can happen in any part of the body, gangrene usually occurs in body parts with small blood vessels, such as toes and fingers, since the arteries supplying these structures are more prone to blockage than larger blood vessels. Gangrene can also occur in organs such as the gallbladder, intestines and muscles.
The primary factor causing gangrene is an abrupt interruption of blood supply to an area of the body. This causes ischemia, which is the lack of adequate oxygen and nutrients in the tissues, leading to eventual cell and tissue death. The most common causes of gangrene include bacterial infections, blood vessel disease such as atherosclerosis and arteriosclerosis, and trauma or injury to the blood vessels.
Gangrene may be classified into the following types:
Dry gangrene is characterized by a dry, discolored, shriveled skin and is mostly caused by small blood vessel disease.
Wet gangrene occurs when the area becomes infected and assumes a swollen "wet" appearance. It should be treated immediately as this form of gangrene is life threatening.
Gas gangrene is caused by clostridium perfringens, a gas-producing bacteria, and is characterized by the presence of gas in the affected area. If the muscles are affected, the overlying skin may become discolored and may assume a swollen, bubbly appearance.
Internal gangrene occurs in the internal organs, the most common being the intestines and gallbladder. This form of gangrene results when blood is blocked off to the organ, as in torsion of the artery in cases of strangulated inguinal hernias.
A form of gangrene affecting the genital region is known as Fournier's gangrene, which can arise from any infection in the genital organs.
Common signs and symptoms of gangrene include pain and swelling, bluish or black skin discoloration, and a foul-smelling discharge from the affected area. Fever due to the infection may also be present. If the infection causing the gangrene has become severe, a condition known as septic shock, which is characterized by a rapid heart rate, low blood pressure, confusion, light-headedness and shortness of breath, can occur.
People who have small blood vessel disease, such as atherosclerosis, are at an increased risk for gangrene. Diabetics are also at risk due to their decreased immune function, which prevents them from effectively fight off infections. Accident victims and persons with serious injuries may be also at risk for gangrene.
Treatment of gangrene includes removal of the dead body tissue through surgery. If the area of the gangrene involves a whole limb, amputation is usually indicated. Antibiotics should be given in cases of gangrene caused by bacterial infections.
The most effective measure to prevent gangrene is to practice proper wound care in cases of injury to prevent infection by bacteria. Wounds should be inspected and cleaned regularly. For people who have chronic conditions such as diabetes or atherosclerosis, proper monitoring of the medical condition may decrease the risk of developing gangrene.