Gas gangrene (also known as clostridial myonecrosis) is a life-threatening necrotizing soft tissue infection commonly caused by the rapid proliferation and spread of Clostridium perfringens from a contaminated wound. The clinical picture includes excruciating muscle pain, edema with subsequent skin discoloration (red-purple to black) and gas production. Crepitus, as well as a feathering pattern of gas in soft tissue imaging, are generally present. Without treatment, gas gangrene is fatal in almost 100% of cases. Surgical debridement in combination with antibiotic therapy reduces this figure by half.
- Clostridium perfringens (> 80% of cases): a gram-positive, obligate anaerobic, spore-forming bacterium
- Less common: C. septicum, C. histolyticum
Path of infection: wounds with compromised blood supply create an optimal anaerobic environment for the proliferation of C. perfringens → necrosis that progresses within 24–36 hours
- Septic surgical wounds or procedures (e.g., bowel and biliary tract surgery, septic abortion) 
- Deep, penetrating wounds (e.g., knife, gunshot)
- Open fractures
Ubiquitous C. perfringens spores contaminate a wound → bacterial reproduction under anaerobic conditions → ↑ secretion of exotoxins, especially C. perfringens alpha-toxin (a phospholipase lecithinase) → degradation of phospholipids → tissue destruction (myonecrosis), inhibition of leukocyte function, and gas production → gas separation into healthy tissue → further colonization and more local tissue destruction → further exacerbation of anaerobic conditions by the development of edema
- Incubation period: hours to days
Local signs and symptoms
- Excruciating muscle pain
- Massive edema with skin discoloration that progresses from bronze to red-purple to black and overlying bullae
- Sweet and foul-smelling or nonodorous discharge produced by anaerobic metabolic products
- Crepitus; : Palpation reveals crackling of the skin due to gas production (skin emphysema)
- Spreading infection (see “Classic signs of inflammation”)
Systemic toxicity 
- Can progress to systemic infection within a few hours
- Early signs
- Multi-organ failure
- Hemolytic anemia
- Kidney and liver failure
Gas gangrene is a medical emergency that can rapidly progress to multiorgan failure.
Perfringens perforates: C. perfringens causes gas gangrene that leads to severe tissue damage.
Subtypes and variants
Spontaneous gas gangrene
- Pathogen: most commonly caused by C. septicum
- Etiology: : typically a complication of an underlying disease, e.g., malignancy (e.g., colon carcinoma), diabetes, or immunosuppression
- Pathophysiology: : Bacteria from the gastrointestinal tract spread hematogenously (due to, e.g., a gastrointestinal lesion or adenocarcinoma of the colon) and reach the muscle tissue.
- Clinical features, diagnosis, and treatment: same as gas gangrene caused by C. perfringens (see sections below)
- Imaging: Radiography, CT, or MRI typically show a characteristic feathering pattern of the soft tissue.
- Gram staining: large, gram-positive rods
- Wound culture: double zone of hemolysis on blood agar
- Blood cultures
- PCR or ELISA for detection of toxin in wound material (not widely available)
- Affected muscle does not bleed or contract, and may be pale or discolored red-purple to black.
Histopathological findings of biopsy 
- Myonecrosis and destruction of surrounding degenerative tissue (muscle, skin fat, subcutaneous tissue)
- Presence of pathogens; without inflammatory infiltrate
- Necrotizing fasciitis
- Vibrio vulnificus infection; : may occur after an open wound is exposed to seawater contaminated with V. vulnificus
- Group A streptococcal infection
- Rhabdomyolysis 
The differential diagnoses listed here are not exhaustive.
The most important steps of management are immediate surgical debridement and antibiotic therapy. Patients should receive supportive therapy and intensive care.
- Surgical exploration and debridement: If applicable, amputation of the affected extremity may be necessary.
- Antibiotic therapy: penicillin plus clindamycin or tetracycline
- Assessment of compartment pressure if compartment syndrome is suspected
- Hyperbaric oxygenation use is controversial.
- Tetanus toxoid if indicated
Mortality rate 
- Untreated: ∼ 100%
- With appropriate treatment: 20–30%