Cause:Clostridium perfringens (C. welchii), or C. novyi; via wound contamination with dirt

Pathophys:Exotoxin produced in tissues leading to cell necrosis via lecithinase, which splits cell walls, collagenase, and other enzymatic activity. CO₂ produced in wounds. Obligate anaerobes; need to live in dead tissue

In most soils; 8% of people carry in stool. Frequent agent in septic abortions.

Sx:Severe pain

Si:Fever, severe toxemia, necrotic skin; sweet smell

Rapid spread leading to death in hours or days

Shock, rapid hemolysis

r/o more benign anaerobic crepitant cellulitis (Ann IM 1975;83:375) in diabetics when E. colior klebsiella anaerobically metabolizes glucose; other anaerobes (Anaerobic Infections (Except Clostridial))

Lab:

Bact:Smear shows large gram-pos sporulating bacilli, which in culture produce lecithinase and CO₂

Chem:Elevated bilirubin (hemolysis)

Xray:Gangrene: tissue gas throughout muscle after 18 h; unlikely to be gas gangrene if occurs earlier and/or without edema and inflammation

Rx:Gangrene: hyperbaric O₂ inactivates the toxin; antitoxin 75000 U iv q 6 h may stop the hemolysis? Antibiotics: high-dose penicillin + gentamicin. Urgent surgery to excise dead tissue