In an involved extremity, the skin is pale and cold as a result of ischemia. Crepitus is present but not prominent. Gram's stain of the wound drainage or of an aspirate from a bleb reveals many clostridia but few leukocytes. Cultures ultimately reveal clostridia, often mixed with several other aerobic or anaerobic organisms. Bacteremia rarely complicates gas gangrene, and acute intravascular hemolysis is usually not a feature.
Early diagnosis is essential for successful treatment of gas gangrene.
The clinical setting, appearance of the involved area, and demonstration of large gram-positive rods in stained smears of the exudate provide support for a presumptive diagnosis. It should be emphasized that C. perfringens does not form spores in tissues. Definition of the specific clostridial syndrome requires surgical exploration and direct examination of healthy muscle for the presence of myonecrosis. In gas gangrene, involved muscle looks cooked and lacks contractility, whereas in cases of clostridial cellulitis, healthy muscle is not affected. Almost all cases of clostridial uterine infection are caused by C. perfringens .