Dry gangrene is a serious and potentially life threatening condition, which causes tissue necrosis (tissue death). The primary cause of tissue death is reduced blood supply to the affected tissues, which results in cell death. This can be secondary to injury or infection, or in people suffering from any chronic health problem effecting blood circulation.
It most commonly occurs in the extremities – the toes, fingers, however internal organs and muscles may also become gangrenous.
There are four main types of gangrene:
1. Dry gangrene
2. Wet gangrene
3. Gas gangrene
4. Internal gangrene
Causes of Dry Gangrene:
Reduced blood flow prevents the required nutrients and oxygen cells need to survive, hence they eventually die. Blood also contains white blood cells to help fight bacteria, parasite and viruses without it infection becomes rife causing increased tissue death.
Risk Factors for Dry Gangrene:
- Age – older people are more prone to circulation complications.
- Diabetes – this effects blood circulation, sensation and the risk of infection.
- Vascular diseases – such as atherosclerosis (narrowed arteries) and blood clots can result in poor blood flow to various parts of the body.
- Injury or surgery – if there was underlying poor blood supply.
- Weakened immune system – people who are immunosuppressed such as AIDS/HIV, chemotherapy, radiotherapy, and organ transplant recipients are more susceptible to the complications of infection.
- Smoking – causes the blood vessels to narrow, resulting in less blood flow.
Symptoms of Dry Gangrene:
- Generally, tissue necrosis develops slowly, unlike some of the other types of gangrene. It is the most common type of tissue death for patients with vascular diseases, generally seen in the elderly.
- A red patch or discolouration appears on the extremity initially (similar to a chilblain).
- The area will gradually become numb and cold.
- When necrosis (tissue death) occurs there may be some pain.
- The area will change from red, to brown, to black.
- The necrotized tissue then shrivels up and eventually falls off.
Prevention of Dry Gangrene:
- Foot care – if you have diabetes you should undertake a diabetes feet check by a podiatrist.
- Smoking – don’t smoke. Smoking damages the blood vessels, increasing the risk.
- Frostbite – if you have been out in the cold for a long time and your skin becomes pale, cold, and numb see your GP.
- Rest or claudication pain– if you are suffering from pain in your legs at night and symptoms of poor perfusion speak to your GP.
Treatment for Dry Gangrene:
Once the tissue is dead it cannot be saved, however the treatment is in preventing the gangrene from spreading.
- Surgery (debridement of dead tissue).
- Vascular intervention– bypass, stents, angioplasty etc. to get more blood flow down to the feet and toes.
- Anticoagulation therapy– (i.e. Warfarin to thin the blood and allow more down to the extremities).
- Skin graft – if damage is extensive the surgeon may remove some healthy skin from one part of the patient’s body and spread it over the affected area to increase healing potential.
- Amputation – if the gangrene is severe it is sometimes necessary to amputate the affected body part, for example a toe, or limb, depending on the blood supply.
- Antibiotics-to fight the infection only after re perfusion is undertaken.
- Hyperbaric oxygen therapy– pressurised chamber to increase oxygen to the wound.
- Maggot therapy– non-surgical way of removing dead tissue. They are specifically bread in a sterile laboratory, and will only feed on dead tissue so the healthy tissue will be unaffected.
- Wound care– dry antimicrobial dressing to minimise infection and wait until the tissue separates and falls off naturally.
Proactive Podiatry is able to assess blood circulation to the feet and educate you on your risk of vascular complications and what can be done to improve circulation and minimise foot injury, infection and pathology.