Gangrene is a necrosis (death) of tissue due to the lack of blood supply. Blood may be obstructed completely, or so diminished that the proper oxygen and nutrients to the tissue cannot be supplied and the tissue dies. There are three main types: dry gangrene, wet gangrene, and gas gangrene.
Symptoms of gangrene is usually a dry or wet wound which is darkened or even completely black. This may progress, or may remain very distinctively separated from viable (living) tissue. Early stages may be seen with swelling and redness. Dry gangrene will appear almost “mummified” and shriveled. Wet gangrene may have a “gooey” appearance with pus and odor. Gas gangrene is more of a fast progression of symptoms with associated cellulitis with swelling and redness.
Causes of a gangrene is from a lack of blood supply. Dry gangrene is typically non-infected and the tissue simply is dying. Wet gangrene and gas gangrene has typically a secondary infection in the tissue causing further destruction. If there is no blood supply to the tissue, a bacterial infection is more difficult to treat since antibiotics travel through the blood. Gas gangrene usually has a anaerobic (not requiring oxygen to survive) bacterial organism associated with it, more commonly Clostridium perfringens. This organism produces a gas in the tissue and may give a symptom of crepitation (sound or feeling of rubbing or popping.)
Diagnosis is first and mainly by clinical suspicion of symptoms. X-rays are usually needed to evaluate the tissue and bone. Bone may become secondarily infected if the tissue is infected, and x-rays may aid in its diagnosis. Gas in the tissues can sometimes be detected on x-rays helping in diagnosis. Cultures are frequently taken of wounds to help determine if an organism is present in a wet or gas gangrene type of wound.
Podiatric Care may include doing nothing at all as dry gangrene, which is not-infected, will eventually demarcate (find the level of good versus bad blood supply) and “fall” off. Treatment of wet and gas gangrene is typically aimed at controlling the infection with use of debridement and antibiotics. A dry gangrene can be considered an emergency due to it being fast spreading. Surgical debridement may be recommended immediately. Due not delay diagnosis or treatment by your physician if you suspect gangrene of your foot or ankle
Surgery is performed in cases where infection is spreading rapidly. A debridement is simply cutting of tissue where needed. Infections usually travel in muscle fascial planes, or along tendon sheaths. As the wound is explored the foot is sometimes “filleted” open. The wound is commonly left open and packed with packing material. This allows for the infection a way to travel out of the foot and the foot can be irrigated with saline or other solution more frequently. Most tissue which has necrosed (died) will be removed to allow for viable (living) tissue to survive. This can produce long term numbness, loss of muscle function, or destroy joint motion. These types of surgery are more of a salvage procedure where all attempts are to keep as much of the foot as possible by sacrificing other parts. A severe foot infection can lead to a hospital admission for an extended period of time.