Basics
Description
- Gas gangrene or clostridial myonecrosis
- An acute, rapidly progressive, gas-forming necrotizing infection of muscle and subcutaneous tissue
- Can be seen in post-traumatic or postoperative situations
- Progressive invasion and destruction of healthy muscle tissue
Etiology
- Clostridial organisms:
- Facultative anaerobic, spore-forming, gram-positive bacillus
- Produces a number of toxins; the most prevalent and lethal is α-toxin.
- Clostridium perfringens is the most common bacterium; found in 80-90% of wounds.
- Other clostridial bacteria include Clostridium novyi, Clostridium septicum, Clostridium histolyticum, Clostridium bifermentans, and Clostridium fallax.
- 2 distinct mechanisms for introduction of clostridial organisms:
- Traumatic and postoperative
- Nontraumatic associated with diabetes mellitus, peripheral vascular disease, alcoholism, IV drug abuse, and malignancies
Diagnosis
Signs and Symptoms
- Sudden severe pain of extremity or involved area
- Low-grade fever
- Tachycardia out of proportion to fever
- Bronzing of the skin over involved area; later can turn purple or red
- Crepitus
- Formation of blebs and bullae
- Thin, serosanguinous exudate and sweet odor
- Rapid local extension
- Obtunded sensorium
- Systemic toxicity
Essential Workup
- History and physical exam with special attention to clinical evidence of crepitus in soft tissue
- Soft tissue x-rays of involved area to detect gas dissecting along fascial planes:
- The absence of gas does not exclude significant disease.
- Stat Gram stain of wound exudate for gram-positive bacillus with paucity of leukocytes
Diagnosis Tests & Interpretation
Lab
- CBC with differential, electrolytes, BUN, and creatinine
- Coagulation studies
- Evaluate for hemolysis
- Stat Gram stain of wound exudates
- Anaerobic cultures of wound or tissue biopsy
Imaging
- Radiographs may reveal soft tissue gas.
- CT if area involves abdomen or flank.
Diagnostic Procedures/Surgery
All patients with gas gangrene must undergo surgical d ©bridement.
Differential Diagnosis
- Cellulitis
- Necrotizing fasciitis
- Nonclostridial myositis and myonecrosis
- Other causes of gas in tissues, as from dissection from respiratory or GI tracts
Treatment
Pre-Hospital
Establish IV and infuse isotonic fluids
Initial Stabilization/Therapy
Manage airway and resuscitate as indicated:
- Rapid sequence intubation as needed.
- Supplemental oxygen:
- Cardiac and oxygen saturation monitors should be placed.
- IV access; consider central venous pressure monitoring; sepsis protocol is appropriate
- Aggressive volume expansion, including crystalloid, plasma, packed RBCs, and albumin if there is septic shock.
Ed Treatment/Procedures
- Parenteral antibiotic therapy:
- Initial empiric therapy should cover Clostridium species and group A Streptococcus as well as mixed aerobes and anaerobes
- Primary definitive therapy: Penicillin G + clindamycin
- Alternative: Ceftriaxone or erythromycin
- If mixed infection: Penicillin + clindamycin, metronidazole, or vancomycin and gram-negative coverage with gentamicin
- Follow local sepsis protocols
- Surgical consultation:
- D ©bridement, amputation, or fasciotomy is required.
- Hyperbaric oxygen (HBO) as adjunctive therapy:
- Early transfer to hyperbaric facility may be lifesaving.
- Lack of randomized trials with HBO but nonrandomized studies suggest benefit
- Tetanus prophylaxis
- Observe for major complications including ARDS, renal failure, myocardial irritability, and DIC.
- Polyvalent antitoxin is not made in US and studies have not demonstrated efficacy:
- Because of the unacceptable hypersensitivity reactions, it is not routinely recommended.
Medication
- Ceftriaxone: 2 g (peds: 100 mg/kg/24h max. 4 g) IV q12h
- Clindamycin: 900 mg (peds: 40 mg/kg/d q6h) IV q8h
- Erythromycin: 1 g (peds: 50 mg/kg/d q6h) q6h IV
- Gentamicin: 2 mg/kg (peds: 2 mg/kg IV q8h) IV q8h
- Metronidazole: 500 mg (peds: Safety not established) IV q8h
- Penicillin G: 24 million IU/24h (peds: 250,000 IU/kg/24h) IV q4-6h
- Tetanus immune globulin: 500 IU IM
- Tetanus toxoid: 0.5 mg IM
First Line
Primary definitive therapy for clostridial species; combination of penicillin G and clindamycin
Follow-Up
Disposition
Admission Criteria
- All patients with gas gangrene and evidence of myonecrosis must be admitted for surgical d ©bridement and IV antibiotics.
- Use of HBO therapy is an important adjunct.
Discharge Criteria
No patient with acute gangrene should be discharged.
Issues for Referral
After stabilization with antibiotics and surgical d ©bridement, consider referral for HBO treatment as an adjunct.
Pearls and Pitfalls
- Bacteremia occurs in about 15% and can progress quickly to intravascular hemolysis.
- HBO as adjunctive therapy to surgical d ©bridement and early antibiotics if patient is hemodynamically stable
Additional Reading
- Bakker DJ. Clostridial myonecrosis (gas gangrene). Undersea Hyperb Med. 2012;39(3):731-737.
- Bryant AE, Stevens DL. Clostridial myonecrosis: New insights in pathogenesis and management. Curr Infect Dis Rep. 2010;12(5):383-391.
- Headley AJ. Necrotizing soft tissue infections: A primary care review. Am Fam Physician. 2003;68(2):323-328.
- Pinzon-Guzman C, Bashir D, McSherry G et al. Clostridium septicum gas gangrene in a previously healthy 8-year old female with survival. J Pediatr Surg. 2013;48(4):e5-e8.
- Stevens DL, Aldape MJ, Bryant AE. Life-threatening clostridial infections. Anaerobe. 2012;18(2):254-259.
Codes
ICD9
- 040.0 Gas gangrene
- 785.4 Gangrene
ICD10
- A48.0 Gas gangrene
- I96 Gangrene, not elsewhere classified
SNOMED
- 372070002 Gangrenous disorder (disorder)
- 80466000 Gas gangrene (disorder)
- 266093005 Gas gangrene caused by clostridium perfringens (disorder)
- 266091007 Gas gangrene caused by clostridium histolyticum (disorder)