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Updated: May 8 2022

Gas Gangrene

Images
https://upload.orthobullets.com/topic/1067/images/clostridium histo.jpg
https://upload.orthobullets.com/topic/1067/images/xr arm.jpg
https://upload.orthobullets.com/topic/1067/images/histo2.jpg
  • Introduction
    • Definition
      • also called clostridial myonecrosis
  • Epidemiology
    • Demographics
      • male:female ratio
        • no sexual predilection
    • Anatomic location
      • buttocks, thigh, perineum
    • Risk factors
      • posttraumatic (associated with C perfringens)
        • car accidents (most common)
        • crush injuries
        • gunshot wounds with foreign bodies
        • burns and frostbite
        • IV drug abuse
      • postoperative
        • bowel resection or perforation
        • biliary surgery
        • premature wound closure
      • spontaneous
        • colon cancer (associated with C. septicum)
        • neutropenia
  • Etiology
    • Pathophysiology
      • Clostridial species
        • Clostridium perfringens (most common), Clostridium novyi, Clostridium septicum
        • found in soil and gut flora
        • gram-positive obligate anaerobic spore-forming rods that produce exotoxins (e.g. C. perfringens alpha toxin)
          • causes muscle necrosis and vessel thrombosis
          • can cause hemolysis and shock
        • incubation period <24h
        • gas produced by fermentation of glucose
          • main component is nitrogen
      • other bacteria include E. coli, Pseudomonas aeruginosa, Proteus species, Klebsiella pneumoniae
  • Presentation
    • History
      • recent surgery to GI or biliary tract
    • Symptoms
      • triad
        • sudden progressive pain out of proportion to injury
          • from thrombotic occlusion of large vessels
        • tachycardia not explained by fever
        • feeling of impending doom
    • Physical exam
      • sweet smelling odor
      • swelling, edema, discoloration and ecchymosis
      • blebs and hemorrhagic bullae
      • "dishwater pus" discharge
      • crepitus
      • altered mental status
  • Imaging
    • Radiographs
      • findings
        • linear streaks of gas in soft tissues
  • Studies
    • Labs
      • Elevated LDH
      • Elevated WBC
      • Metabolic acidosis and renal failure
    • Histology
      • Gram stain reveals Gram-positive bacilli
      • absence of neutrophils
        • lack of acute inflammatory response is hallmark of gas gangrene
    • Culture
      • blood culture rarely grows Clostridial species
  • Differential
    • Necrotizing fasciitis
  • Treatment
    • Nonoperative
      • high dose IV antibiotics
        • 1st line is penicillin G and clindamycin
        • alternative treatment is erythromycin, tetracycline or ceftriaxone
          • clindamycin and tetracycline inhibit toxin synthesis
      • hyperbaric O2
        • indications
          • useful adjunct
        • outcomes
          • effectiveness of HBO2 is inconclusive
    • Operative
      • radical surgical debridement with fasciotomies
        • indications
          • 1st line treatment is surgical
  • Complications
    • Shock
    • Renal failure
      • both mediated by TNF alpha, IL-1, IL-6
  • Prognosis
    • Overall 25% mortality
      • 50% mortality if bacteremic
      • 100% mortality if treatment is delayed
    • Poorer prognosis for older patients with comorbidities
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