Rosen & Barkin's 5-Minute Emergency Medicine Consult (475 page)

• Neonates: Omphalitis and circumcision are predisposing factors.
  
• Risk factors for children:
  
  • Chronic illness
    
  • Surgery
    
  • Recent varicella infection (58-fold increased risk of GABHS NSTI)
    
  • Congenital and acquired immunodeficiencies
    

DIAGNOSIS

• Fever
  
• Altered mental status
  
• Chronic medical conditions
  
• IV drug use
  
• Skin:
  
  • Rapid progression of pain and swelling of involved area
    
  • In 1st 24 hr, rapid development of local swelling, heat, erythema, and tenderness
    
  • 24–48 hr: Purple and blue discoloration, blisters and bullae develop (often hemorrhagic)
    
  • Foul-smelling thin fluid (from necrosis of fat and fascia)
    

• Systemic toxicity:
  
  • Fever
    
  • Tachycardia
    
  • Tachypnea
    
  • Hypotension
    
  • Altered mental status
    
• Pain out of proportion to physical findings
  
• Skin:
  
  • Erythema
    
  • Tense edema
    
  • Grayish or other discolored wound drainage
    
  • Vesicles or bullae
    
  • Necrosis
    
  • Ulcers
    
  • Crepitus (pathognomonic but present in only 10–37% of cases)
    
  • Pain that extends past margin of infection
    

• Most common presenting symptoms
  
  • Localized pain (97%)
    
  • Rash (73%)
    
  • Hypotension, altered mental status, and other signs of shock are much less common
    

• Diagnosis can be difficult
  
• Careful exam for the aforementioned signs and symptoms in high-risk patients
  
• NSTIs must be suspected in patients who appear very ill and have pain out of proportion to physical findings
  
• Diagnosis may require incision and probing of tissue
  

• CBC with differential
  
• Electrolytes
  
• BUN and creatinine
  
• Disseminated intravascular coagulation panel
  
• Calcium level: Hypocalcemia can develop from extensive fat necrosis
  
• Gram stain and aerobic/anaerobic cultures of wound or tissue biopsy
  

• X-rays to detect soft tissue gas: Pathognomonic, but present in only 39–57% of cases
  
• CT scan:
  
  • May be more helpful than plain x-rays in detecting SC air
    
  • May also identify deep abscess or other cause of infection
    
• MRI:
  
  • Can delineate extent of spread of the infection
    
• US:
  
  • Fascial thickening
    
  • Fluid in the fascial plane
    
  • SC soft tissue edema
    

• All patients with suspected NSTI must undergo surgical debridement
  
• Deep incisional biopsy and cultures are the gold standard for diagnosis
  

• Cellulitis
  
• Gas gangrene
  

TREATMENT

• IV fluid resuscitation
  
• Manage airway as necessary.
  

Manage airway and resuscitate as indicated:

• Rapid-sequence intubation as needed
  
• Supplemental oxygen, monitor, evaluate for acid–base disturbances
  
• IV access, CVP line may be needed
  
• Aggressive volume expansion including crystalloid, plasma, packed RBCs, and albumin
  

• Antibiotics: Broad coverage of aerobic gram-positive and gram-negative organisms and anaerobes
  
• Acceptable combination therapy:
  
  • Penicillin or cephalosporin
    +
    an aminoglycoside or fluoroquinolone
    +
    anaerobic coverage with either clindamycin or metronidazole
    
• Treat methicillin-resistant Staphylococcus aureus (MRSA) until excluded:
  
  • Vancomycin
    
  • Linezolid
    
  • Daptomycin
    
• Surgical consultation:
  
  • Early debridement of all necrotic tissue with fasciotomy and drainage of fascial planes is paramount
    
• Hyperbaric oxygen as an adjunct:
  
  • Early transfer to hyperbaric facility may result in greater tissue salvage
    
• IV immunoglobulin (IVIG):
  
  • Controversial
    
  • May be beneficial in NSTI caused by group A streptococcal infection
    
• Observe for major complications including acute respiratory distress syndrome, renal failure, myocardial irritability, and DIC
  

• Ceftriaxone: 2 g (peds: 100 mg/kg/24 h; max. 4 g) IV q24h
  
• Ciprofloxacin: 400 mg IV q12h
  
• Clindamycin: 900 mg (peds: 40 mg/kg/d q6h) IV q8h
  
• Daptomycin: 4 mg/kg IV q24h
  
• Gentamicin: 2 mg/kg (peds: 2 mg/kg IV q8h) IV q8h
  
• Doxycycline: 100 mg IV q12h
  
• Imipenem/cilastatin: 250–1,000 mg IV q6–8h
  
• Levofloxacin: 750 mg IV q24h
  
• Linezolid: 600 mg PO/IV q12h (peds: 30 mg/kg/d PO/IV div. q8h)
  
• Meropenem: 1 g (peds: 20–40 mg/kg up to 2 g/dose) IV q8h
  
• Metronidazole: 500 mg (peds: Safety not established) IV q8h
  
• Penicillin G: 24 million U q24h (peds: 250,000 IU/kg/24h) IV q4–6h
  
• Piperacillin/tazobactam 3.375–4.5 g (peds: 240 mg/kg/d of piperacillin div. q8h) IV q6h
  
• Tigecycline: Start 100 mg IV × 1; 50 mg IV q12h
  
• Vancomycin: 10–15 mg/kg IV q12h (peds: 10–15 mg/kg IV q6–8h)
  

• Type I infections:
  
  • Piperacillin/tazobactam + clindamycin + ciprofloxacin/levofloxacin
    
  • Imipenem/cilastatin
    
  • Meropenem
    
• Type II infections:
  
  • Clindamycin + penicillin (or linezolid or vancomycin)
    
• Type III infections:
  
  • Clindamycin + penicillin
    
• Type IV infections:
  
  • Doxycycline
    

FOLLOW-UP

• All patients with an NSTI
  must be admitted
  for surgical debridement and IV antibiotics
  
• Early hyperbaric oxygen therapy may be an important adjunct
  

No patient with NSTI should be discharged

After stabilization with antibiotics and surgical debridement, consider referral for hyperbaric oxygen treatment as an adjunct.

• The clinician must have a high index of suspicion for NSTI, as initial skin findings may be unimpressive
  
• Pain out of proportion to exam may be a key finding
  
• Mortality will be near 100% if treatment is ONLY with antimicrobials
  
• Scoring systems for NSTI have limited utility
  
• 4 tenets of treating NSTI:
  
  • Fluid resuscitation and management of metabolic disturbances
    
  • Early antimicrobial therapy
    
  • Surgical debridement
    
  • Treating organ failure
    

• Anaya DA,Bulger EM,Kwon YS, et al. Predictingdeath in necrotizing soft tissue infections: A clinical score.
  Surg Infect(Larchmt)
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• Anaya DA, Dellinger EP. Necrotizing soft-tissue infection: Diagnosis and management.
  Clin Infect Dis
  . 2007;44:705–710.
  
• Cainzos M, Gonzalez-Rodriguez FJ. Necrotizing soft tissue infections.
  Curr Opin Crit Care
  . 2007;13:433–439.
  
• Jamal N, Teach SJ. Necrotizing fasciitis.
  Pediatr Emer Care
  . 2011;27:1195–1199.
  
• Lancerotto L,Tocco I,Salmaso R, et al. Necrotizingfasciitis: Classification, diagnosis, and management.
  J Trauma Acute CareSurg
  .2012;72:560–566.
  
• Ustin JS, Malangoni MA. Necrotizing soft-tissue infections.
  Crit Care Med
  . 2011;39:2156–2162.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Cellulitis
  
• Erysipelas
  
• MRSA, Community Acquired
  
• Gangrene
  

CODES