Gas gangrene

Diagnostic approach

• ABCDE approach
• Targeted clinical evaluation
• CBC
• CMP
• Lactate
• Blood cultures
• Imaging (e.g., x-ray, CT)
• See “Diagnosis of gas gangrene.”

Gas gangrene is a clinical diagnosis; do not delay treatment to perform diagnostic studies.

Management checklist

• Manage septic shock.
• Administer broad-spectrum antibiotics. See “Necrotizing SSTI” in “Empiric antibiotics for SSTIs.”
• Consult surgery immediately for debridement.
• Perform emergency preoperative assessment.
• See “Treatment of gas gangrene.”

Gas gangrene or clostridial myonecrosis is a life-threatening necrotizing soft tissue infection most commonly caused by the rapid proliferation and spread of Clostridium perfringens. Traumatic gas gangrene occurs in wounds with compromised blood supply, while spontaneous gas gangrene occurs from hematogenous spread from lesions in the gastrointestinal tract. Gas gangrene manifests with excruciating muscle pain, edema with subsequent skin discoloration (red-purple to black), and signs of sepsis. Gas production leads to crepitus and a feathering pattern of gas on imaging. Treatment involves immediate surgical debridement with removal of all necrotic tissue in combination with antibiotic therapy. Even with treatment, gas gangrene has a high mortality rate.

Traumatic gas gangrene ^[1]

• Pathogen ^[1]
  • Clostridium perfringens (> 80% of cases): a gram-positive, obligate anaerobic, spore-forming bacterium
  • Less common: C. septicum, C. histolyticum, C. novyi, C. sordellii
• Source: wounds with compromised blood supply create an optimal anaerobic environment for C. perfringens ^[1]
  • Septic surgical wounds or procedures (e.g., bowel and biliary tract surgery)
  • Deep, penetrating wounds (e.g., knife, gunshot)
  • Open fractures
  • Childbirth, abortion, and other gynecological procedures

Spontaneous gas gangrene ^[2]

• Pathogen: most commonly caused by C. septicum
• Source: hematogenous spread from lesions in the gastrointestinal tract
  • Gastrointestinal malignancy (e.g., colon carcinoma)
  • Diverticulitis

Ubiquitous C. perfringens spores contaminate a wound OR C. septicum spreads hematogenously from lesions in the gastrointestinal tract → 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; initially, pain out of proportion to physical examination
  • 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 signs and symptoms
  • Can progress to systemic infection within a few hours
  • Early signs
    • Fever
    • Tachycardia
    • Altered mental status
  • Late signs
    • Shock
    • Multiorgan failure
    • Hemolytic anemia
    • ARDS
    • 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.

Histopathological findings include: ^[3]

• Myonecrosis and destruction of surrounding degenerative tissue (muscle, fat, subcutaneous tissue)
• Pathogens without inflammatory infiltrate

Gas gangrene is a clinical diagnosis; do not delay treatment to perform diagnostic studies.

Approach ^[1][2][4]

• Perform a septic workup.
• Obtain imaging for diagnostic uncertainty and/or to assess extent of infection.
• Confirm the diagnosis with surgical exploration and microbiological studies.

Laboratory studies ^[1][2]

• Septic workup: including CBC, CMP, lactate, and blood cultures ^[3]
• Additional microbiological studies
  • Gram staining: large, gram-positive rods
  • Wound or tissue culture: double zone of hemolysis on blood agar ^[5]

Imaging ^[2][4]

• Modalities: ultrasound, x-ray, CT, or MRI depending on availability and patient stability
• Findings: characteristic feathering pattern of the soft tissue caused by gas pockets between muscle fibers

• Necrotizing fasciitis
• Vibrio vulnificus infection; : may occur after an open wound is exposed to seawater contaminated with V. vulnificus
• Group A streptococcal infection
• Rhabdomyolysis
• Pyomyositis
• Phlegmasia cerulea dolens
• Acute compartment syndrome
• Acute limb ischemia

The differential diagnoses listed here are not exhaustive.

Initial management ^[4][6]

• Stabilize patients using the ABCDE approach.
• Manage septic shock with immediate hemodynamic support.
• Begin empiric broad-spectrum antibiotics.
• Consult surgery immediately for debridement.
• Perform emergency preoperative assessment.
• Transfer to the OR and/or admit to an ICU.

Gas gangrene requires prompt surgical exploration and debridement.

Antibiotic therapy ^[6][7]

• Empiric broad-spectrum antibiotics
  • Initiate broad-spectrum antibiotics as soon as gas gangrene is suspected.
  • See “Necrotizing SSTI” in “Empiric antibiotics for SSTIs” for suggested regimens.
• Pathogen-specific antibiotic therapy
  • Initiate pathogen-specific antibiotics as soon as clostridial infection is confirmed.
  • First-line: Penicillin G PLUS clindamycin ^[6][7]
  • Alternatives ^[8]
    • A carbapenem (e.g., meropenem, ertapenem) PLUS clindamycin
    • Clindamycin monotherapy

Surgical and wound management ^[2][6]

• Surgical management
  • Prompt surgical exploration and debridement of all necrotic and devitalized tissue
  • Potential amputation if an extremity is affected
• Wound management
  • Reevaluate the affected area frequently; repeated debridement is often required.
  • Hyperbaric oxygen therapy (HBOT) may be considered as an adjunctive treatment, if available. ^{[6][7][9][10]}
  • Monitor for and treat complications (e.g., compartment syndrome).

• Mortality rate ^[11]
  • Untreated: ∼ 100%
  • With treatment: 20–30%