Author:
Karen B.Van Hoesen
Stephen R.Hayden
Description
- Gas gangrene or clostridial myonecrosis
- An acute, rapidly progressive, gas-forming necrotizing infection of healthy muscle and subcutaneous tissue
- Develops contiguously from a nearby area or hematogenously
- Can be seen in posttraumatic 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
- α-toxin is largely responsible for tissue destruction
- Other clostridial bacteria include C. novyi, C. septicum, C. histolyticum, C. bifermentans, and C. fallax
- 2 distinct mechanisms for introduction of clostridial organisms:
- Traumatic and postoperative
- Spores introduced in deep tissue, proliferate in anaerobic environment
- Nontraumatic associated with diabetes mellitus, peripheral vascular disease, alcoholism, IV drug abuse, and malignancies
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
Physical Exam
- Palpation of crepitus in soft tissue is most sensitive physical finding
- Distal neurovascular exam
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
Diagnostic Tests & Interpretation
Lab
- CBC with differential, electrolytes, BUN, and creatinine
- Inflammatory markers; ESR, CRP
- Coagulation studies
- Evaluate for hemolysis
- Stat Gram stain of wound exudates
- Anaerobic cultures of wound or tissue biopsy
- Blood cultures
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 debridement
Differential Diagnosis
- Cellulitis
- Necrotizing fasciitis
- Nonclostridial myositis and myonecrosis
- Other causes of gas in tissues, as from dissection from respiratory or GI tracts
Prehospital
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
- Piperacillin-tazobactam PLUS clindamycin
- 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:
- Debridement, amputation, or fasciotomy is required
- Hyperbaric oxygen (HBO) as adjunctive therapy:
- Early transfer to hyperbaric facility may be lifesaving
- Lack of rand omized trials with HBO but nonrand omized studies suggest benefit
- Tetanus prophylaxis
- Observe for major complications including ARDS, renal failure, myocardial irritability, and DIC
- Polyvalent antitoxin is not made in the U.S. and studies have not demonstrated efficacy:
- Because of the unacceptable hypersensitivity reactions, it is not routinely recommended
Medication
- Ceftriaxone: 2 g IV q12h (peds: 100 mg/kg/24 hr max 4 g)
- Clindamycin: 900 mg IV q8h (peds: 40 mg/kg/d q6h)
- Erythromycin: 1 g q6h IV (peds: 50 mg/kg/d q6h)
- Gentamicin: 2 mg/kg IV q8h (peds: 2 mg/kg IV q8h)
- Metronidazole: 500 mg IV q8h (peds: Safety not established)
- Penicillin G: 24 million U/24 hr IV q4-6h (peds: 250,000 U/kg/24 hr)
- Piperacillin-tazobactam: 4.5 g IV q8h (peds: 2-9 mo: 240 mg/kg/d IV div q8h, 9 mo <40 kg: 300 mg/kg/d IV div q8h, >40 kg: 3.375-4.5 g IV q8h)
- Tetanus immune globulin: 500 units IM
- Tetanus toxoid: 0.5 mg IM
Disposition
Admission Criteria
- All patients with gas gangrene and evidence of myonecrosis must be admitted
- 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 debridement, referral for HBO treatment as an adjunct