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Gas gangrene
Definition:
Gas gangrene is a severe form of gangrene (tissue death) usually caused by Clostridium perfringens (see also necrotizing subcutaneous infection). It can also be from Group A Streptococcus. Staphlococcus aureus and Vibrio vulnificus can also cause similar infections. Alternative Names:
Tissue infection - Clostridial; Gangrene - gas; Myonecrosis; Clostridial infection of tissues Text Continues Below
Causes, incidence, and risk factors:
Gas gangrene occurs as a result of infection by Clostridium bacteria that, under anaerobic (low oxygen) conditions, produce toxins that cause the tissue death and associated symptoms. Gas gangrene is rare, with only 1,000 to 3,000 cases occurring in the United States annually. Gas gangrene generally occurs at the site of trauma or a recent surgical wound. About a third of cases occur spontaneously. Patients who develop this disease spontaneously often have underlying vascular disease (atherosclerosis or hardening of the arteries), diabetes, or colon cancer. The onset of gas gangrene is sudden and dramatic. Inflammation begins at the site of infection as a pale-to-brownish-red and extremely painful tissue swelling. Gas may be felt in the tissue as a crackly sensation when the swollen area is pressed with the fingers. The margins of the infected area expand so rapidly that changes are visible over a few minutes. The involved tissue is completely destroyed. Clostridium bacteria produce many different toxins, four of which (alpha, beta, epsilon, iota) can cause potentially fatal syndromes. In addition, they cause tissue death (necrosis), destruction of blood (hemolysis), local decrease in circulation (vasoconstriction), and leaking on the blood vessels (increased vascular permeability).
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