Updated: 10/17/2017

Necrotizing Fasciitis

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Snapshot
  • A 38-year-old man presents to the emergency department for severe pain in his right foot. He reports that these symptoms are accompanied by fever with the leg turning red. He denies any recent trauma but admits to injecting heroin via his lower extremity since he can no longer do so in his arms. Medical history is significant for opioid-use disorder and hepatitis C infection. On physical exam, tenderness to palpation of the affected area is out of proportion to his superficial skin findings. 
Introduction
  • Clinical definition
    • infection of the superficial fascia that is life threatening
  • Epidemiology
    • risk factors
      • diabetes mellitus
      • chronic corticosteroid use
      • alcohol abuse
      • injection drug use
  • Etiology
    • polymicrobial infection
      • most common (70-80%)
      • contains aerobic and anaerobic organisms
        • aerobes
          • Streptococcus spp. (most common)
        • anaerobes
          • Bacteroides spp.
          • Peptostreptococcus spp. 
    • monomicrobial infection
      • most commonly caused by group A Streptococcus
  • Pathogenesis
    • inciting infection at tissue site can be accomplished via
      • hematogenous spread
      • direct inoculation
    • infection rapidly spreads leading to
      • vascular occlusion → ischemia and necrosis
      • crepitus in cases of gas forming organisms (e.g., Clostridium) and anaerobic organisms
  • Prognosis
    • increased mortality and risk of amputation
Presentation
  • Symptoms
    • severe pain
      • out of proportion to superficial findings of the affected area
    • fever
  • Physical exam
    • tenderness to palpation
    • palpable crepitus
      • secondary to methane and CO2 production
    • erythema
    • bullae, blisters, or ulcers
    • cutaneous necrosis
    • progression of disease despite antibiotic treatment
Studies
  • Labs
    • ↑↑ C-reactive protein
    • ↑ creatine kinase
    • ↑ white blood cell count (BUN) and blood urea nitrogen (BUN)
  • Intraoperative studies
    • Gram stain
    • biopsy
  • Diagnostic criteria
    • based on clinical suspicion and confirmed intraoperatively with surgical debridement
      • labs or imaging do not override clinical judgement
Differential
  • Cellulitis
  • Staphylococcus scalded skin syndrome
  • Gas gangrene
Treatment
  • Management approach
    • promp surgical debridement is the mainstay of treatment along with antibiotic treatment
  • Medical
    • intravenous empiric antibiotics
      • indication
        • a treatment component of necrotizing fasciitis directed against likely organisms
          • e.g., antibiotics that target group A Streptococcus, gram-negative organisms, anaerobes, and methicillin-resistant Staphylococcus aureus (MRSA)
  • Operative
    • surgical debridement
      • indication
        • a necessary component of treatment that also confirms the diagnosis
Complications
  • Streptococcal toxic shock syndrome
  • Compartment syndrome
  • Myositis
  • Muscle necrosis
 

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