Gas Gangrene
Gas gangrene (clostridial myonecrosis) is a life-threatening infection of muscle tissue caused mainly by the anaerobic bacterium Clostridium perfringens and several other Clostridium species.
Gas gangrene is a fast-spreading clostridial infection of muscle tissue that quickly leads to death if untreated. The bacteria produce gas that becomes trapped in the infected tissue. Several thousand cases occur in the United States every year. Gas gangrene usually develops after trauma or surgery, although spontaneous infections can occur--usually in people with colon cancer or leukemia. Surgery on the colon and gallbladder are the procedures most likely to be complicated by gas gangrene. High-risk injuries are those that become contaminated with dirt and vegetable matter or that contain crushed and dead tissue. People with open fractures and frostbite are also particularly susceptible to gas gangrene.
Symptoms and Diagnosis
Gas gangrene produces severe pain in the infected area. Initially, the area is swollen and pale, but eventually turns red, then bronze, and finally blackish green. Large blisters often form. Gas bubbles may be visible in the blister fluid or may be felt under the skin. The odor of any wound drainage is described as sweet or mousy, unlike the putrid odor typical of other anaerobic infections.
As the infection progresses, the person becomes sweaty and very anxious; vomiting may also occur. Rapid heart rate and rapid breathing are common. These effects are caused by toxins produced by the bacteria. Typically, the person remains very alert until late in the illness, when very low blood pressure (shock) and coma develop, followed rapidly by death.
The initial diagnosis of gas gangrene is based on the person's symptoms and a physical examination. Finding gas bubbles in the muscle tissue on x-ray increases a doctor's suspicion of a clostridial infection, but gas bubbles may also occur with non-clostridial anaerobic infections. Examination of secretions from the wound under a microscope may reveal the clostridia, and cultures can confirm their presence--but because gas gangrene is so rapidly fatal, treatment is always begun before the culture results are available.
Prevention, Prognosis, and Treatment
Cleaning wounds thoroughly and removing foreign objects and dead tissue is the best way to prevent clostridia from infecting a wound. Intravenous antibiotics are used before, during, and after abdominal surgery to prevent postoperative infection. There are no vaccines to prevent clostridial infection.
Without treatment, gas gangrene is fatal within 48 hours. Even with treatment, death occurs in about one of eight people with infection of a limb and in about two of three people with infection on the trunk.
If gas gangrene is suspected, treatment must begin immediately. High doses of antibiotics, typically penicillin and clindamycin, are given, and all dead and infected material is removed surgically. About one of five people with gas gangrene in a limb requires amputation of the infected limb. Treatment in a high-pressure oxygen (hyperbaric oxygen) chamber is of uncertain value; moreover, such chambers are not readily available.
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