Gangrene

DEFINITION

Gangrene refers to the death of body tissue due to a lack of blood flow or a bacterial infection. Gangrene most commonly affects the extremities, including your toes, fingers and limbs, but it can also occur in your muscles and internal organs.

Your chances of developing gangrene are higher if you have an underlying condition that can damage your blood vessels and affect blood flow, such as diabetes or atherosclerosis.

Treatments for gangrene include surgery to remove dead tissue, antibiotics and other approaches. The prognosis for recovery is better if gangrene is identified early and treated quickly.

CAUSES

Gangrene may occur due to one or both of the following:

• Lack of blood supply. Your blood provides oxygen, nutrients to feed your cells, and immune system components, such as antibodies, to ward off infections. Without a proper blood supply, cells can’t survive, and your tissue decays.
• Infection. If bacteria thrive unchecked for long, infection can take over and cause your tissue to die, causing gangrene.

Types of gangrene

• Dry gangrene. Dry gangrene is characterized by dry and shriveled skin ranging in color from brown to purplish-blue to black. Dry gangrene may develop slowly. It occurs most commonly in people who have a blood vessel disease, such as atherosclerosis.
• Wet gangrene. Gangrene is referred to as “wet” if there’s a bacterial infection in the affected tissue. Swelling, blistering and a wet appearance are common features of wet gangrene.

  It may develop after a severe burn, frostbite or injury. It often occurs in people with diabetes who unknowingly injure a toe or foot. Wet gangrene needs to be treated immediately because it spreads quickly and can be fatal.

• Gas gangrene. Gas gangrene typically affects deep muscle tissue. If you have gas gangrene, the surface of your skin may initially appear normal.

  As the condition progresses, your skin may become pale and then evolve to a gray or purplish-red color. A bubbly appearance to your skin may become apparent, and the affected skin may make a crackling sound when you press on it because of the gas within the tissue.

  Gas gangrene is commonly caused by infection with the bacterium Clostridium perfringens, which develops in an injury or surgical wound that’s depleted of blood supply. The bacterial infection produces toxins that release gas — hence the name “gas” gangrene — and cause tissue death. Like wet gangrene, gas gangrene can be life-threatening.

• Internal gangrene. Gangrene affecting one or more of your organs, such as your intestines, gallbladder or appendix, is called internal gangrene. This type of gangrene occurs when blood flow to an internal organ is blocked — for example, when your intestines bulge through a weakened area of muscle in your abdomen (hernia) and become twisted.

  Internal gangrene may cause fever and severe pain. Left untreated, internal gangrene can be fatal.

• Fournier’s gangrene. Fournier’s gangrene involves the genital organs. Men are more often affected, but women can develop this type of gangrene as well. Fournier’s gangrene usually arises due to an infection in the genital area or urinary tract and causes genital pain, tenderness, redness and swelling.
• Progressive bacterial synergistic gangrene (Meleney’s gangrene). This rare type of gangrene typically occurs after an operation, with painful skin lesions developing one to two weeks after surgery.

SYMPTOMS

When gangrene affects your skin, signs and symptoms may include:

• Skin discoloration — ranging from pale to blue, purple, black, bronze or red, depending on the type of gangrene you have
• A clear line between healthy and damaged skin
• Severe pain followed by a feeling of numbness
• A foul-smelling discharge leaking from a sore

If you have a type of gangrene that affects tissues beneath the surface of your skin, such as gas gangrene or internal gangrene, you may notice that:

• The affected tissue is swollen and very painful
• You’re running a fever and feel unwell

A condition called septic shock can occur if a bacterial infection that originated in the gangrenous tissue spreads throughout your body. Signs and symptoms of septic shock include:

• Low blood pressure
• Fever, possibly, though temperature may also run lower than the normal 96.8 F (36 C)
• Rapid heart rate
• Lightheadedness
• Shortness of breath
• Confusion

When to see a doctor

Gangrene is a serious condition and needs immediate treatment. Call your doctor right away if you have persistent, unexplained pain in any area of your body along with one or more of the following signs and symptoms:

• Persistent fever
• Skin changes — including discoloration, warmth, swelling, blisters or lesions — that won’t go away
• A foul-smelling discharge leaking from a sore
• Sudden pain at the site of a recent surgery or trauma
• Skin that’s pale, hard, cold and numb