Gangrene

Gangrene is a dangerous and potentially fatal condition that happens when the blood flow to a large group of tissues is cut off. This causes them to rot and die. Although gangrene often turns the affected skin a greenish-black, the word gangrene is not related to green, but rather to the condition itself. It comes from Greek and Latin words for a gnawing sore or decayed tissue. 

Causes

Gangrene happens when blood supply to certain tissues is stopped by an infection, an injury such as a burn or combat wound, or a chronic disease. Chronic diseases that harm the circulatory system include diabetes, peripheral artery disease, and Raynaud's disease. These can often lead to gangrene. Traumatic injuries like burns or an infected dog bite may also stop blood flow. Severe cases of frostbite can also lead to gangrene. Frostbite is a condition in which the skin freezes.

Symptoms

Symptoms of gangrene depend on its location and cause. Dry gangrene usually starts with a red line around the affected area. This area then turns black.

These are other symptoms of gangrene:

  • Coldness and numbness in the affected area

  • Pain in or beyond the affected area

  • Redness and swelling around a wound

  • Sores that keep cropping up in the same place

  • Persistent, unexplained fever (temperature higher than 100.4 degrees Fahrenheit (38 degrees Celsius) 

  • A foul-smelling wound

  • Striking discoloration of the skin, with shades of greenish-black, blue, red, or bronze

  • Pus or discharge from a wound

  • Blisters and a crackling sound under the skin

  • Confusion, pain, fever, and low blood pressure, especially if the gangrene is internal

  • Shock

The earlier gangrene is treated, the more successful the treatment is likely to be. So if you have any of the above symptoms, seek immediate medical attention.

Diagnosis

If you have symptoms of gangrene, your medical team will perform a physical exam to check for signs of tissue death. They may also ask you about any chronic health conditions you have that could be related to the gangrene.

Your doctor may also want to do lab tests to check for gangrene. A higher than normal amount of white blood cells, for example, can mean you have an infection. Your doctor may take samples of tissue or fluid from the affected area and looked at in the lab. If your doctor suspects internal gangrene, he or she may order imaging tests or surgery to find out for sure.

Treatment

Treatment of gangrene will usually consist of one or more of these procedures:

  • Antibiotics. These medications can be used to kill bacteria in the affected area.

  • Surgery to remove the dead tissue. This is called debridement. It can help keep the gangrene from spreading to healthy tissues nearby. In cases where the gangrene is widespread, a finger, toe, or even a limb may need to be amputated.

  • Maggot debridement. This is a nonsurgical alternative to traditional debridement. During this procedure, clean fly larvae are placed on the affected area to eat away dead tissue and remove bacteria. This is a painless procedure.

  • Hyperbaric oxygen therapy. During this procedure, you are placed in a special pressurized chamber that administers oxygen at high pressures, forcing more oxygen into the affected area. This can speed healing and help kill bacteria. This treatment is especially effective in people who develop gangrene from diabetic foot ulcers.

  • Vascular surgery. If your gangrene is caused by poor blood flow, your doctor may recommend surgery to improve circulation. People whose gangrene is a result of a blocked artery, for example, may have bypass surgery or an angioplasty to fix the problem.

Prognosis

Gangrene is a medical emergency. The outlook with gangrene depends on the location and size of the affected area, as well as any other medical conditions you might have. Gangrene is often life-threatening, so immediate medical attention is crucial.