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Internal Medicine

Gas gangrene

Rapidly spreading edematous myonecrosis occurring characteristically in association with severe wounds of extensive muscle masses contaminated with pathogenic clostridia, particularly C. perfringens.

Cover image: Gas gangrene of the right leg and pelvis, showing swelling and discoloration of the right thigh, bullae, and palpable crepitus. The patient, in shock at the time this photograph was taken, underwent a hemipelvectomy (right leg amputation) and died less than eight hours later. | By Engelbert Schröpfer, Stephan Rauthe and Thomas Meyer. - Diagnosis and misdiagnosis of necrotizing soft tissue infections: three case reports. Cases J 2008, 1:252. doi: 10.1186/1757-1626-1-252, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=6886224

Rapidly spreading edematous myonecrosis occurring characteristically in association with severe wounds of extensive muscle masses contaminated with pathogenic clostridia, particularly C. perfringens.

(Oakley, 1954)
  • Previously known as malignant edema

Etiology

  • Contaminated, manured or cultivated soil
    • Intestines
    • Fecal flora
  • Disease of war
    • Extensive wounds + heavy contamination
      • Crush wounds, amputations, ischaemic limb, gunshot wounds, war wounds
  • Anerobic environment in wounds

Organisms:

  • Clostridium welchii (perfringens) (M/C, 60%)
  • Clostridium oedematiens
  • Clostridium septicum
  • Clostridium histolyticum

Pathophysiology

  • H2 + CO2 → Characteristic gas formation

Clostridial myonecrosis

Following toxins are mediated in the process:
  • α-toxin or Phospholipase C (lecithinase) → Anaerobic (clostridial) myositis
  • Clostridium perfringens enterotoxin (CPE) → Food poisoning and other gastrointestinal illnesses
  • Haemolysin → Hemolysis
  • Hyaluronidase → Rapid spread of gas gangrene
  • Proteinase

Presentation

  • Increasing pain, tenderness and oedema of affected part
  • Systemic signs of toxaemia
  • Discharge from wound:
    • Initially: Thin and watery
    • Later: Profuse and serosanguinous
  • Crepitant tissues (due to accumulation of gas)
  • Profuse toxaemia and prostration
  • Death due to circulatory failure

Complications:

  • Septicaemia, toxaemia
  • Renal failure, liver failure
  • Circulatory failure, DIC, secondary infection
  • Death

Diagnosis

  • SPECIMENS
    • Films
    • Exudates
    • Necrotic tissue and muscle fragments
  • MICROSCOPIC EXAMINATION
    • Gram-stained films:
      • Gram-positive bacilli without spores: C. perfringens
      • Citron bodies: C. septicum
      • Large bacilli with subterminal spores: C. novyi
      • Slender bacilli with round, terminal spores: C. tetani tetanomorphum
  • CULTURE
    • Fresh and heated blood agar
    • Serum or egg yolk agar: Nagler reaction
    • Robertson’s cooked meat broth
    • Reverse CAMP test

Management

Prevention:

  • Debridement of wounds
  • Avoid suturing of devitalized wounds
  • Adequate cleaning
  • Prophylactic Penicillin
  • Fumigation of ward/OT after gas gangrene patient for 24-48 hours

Treatment:

Put patient in hyperbaric oxygen chamber
  • Excision & debridement of wound
  • Fluid & electrolytes
  • Injection Benzylpenicillin
  • Fresh blood transfusion
  • Polyvalent antiserum (25000 units IV 6 hourly)
  • If severe: Guillotine amputation

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