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necrotizing fasciitis

Etiology: 1) bacterial infection a) Streptococcus pyogenes b) Staphylococcus epidermidis c) Pseudomonas aeruginosa d) Vibrio vulnificus 2) risk factors a) varicella lesions b) intramuscular injections, injection drug use c) penetrating trauma d) omphalitis e) dental abscess f) toxic shock g) wound exposure to seawater (Vibrio vulnificus) Pathology: - necrosis of skin & underlying fascia - cutaneous nerve destruction [1] - widespread tissue destruction [7] * histopathology image [5] Clinical manifestations: - fever/chills - 'woody' induration or cellulitis - pain out of proportion to examination - edema - skin discoloration, retiform purpura [1], bullae - friable superficial fascia [7] - gray exudate without pus [7] - vesiculations, ecchymosis, crepitus, anesthesia & necrosis are signs of advanced disease - in children, the abdominal wall & gluteal regions most commonly involved - manifestations of sepsis may be present - hypotension - altered mental status * images [5] Laboratory: - complete blood count (CBC) may show leukocytosis - blood cultures - chemistry panel may show - metabolic acidosis - abnormal liver function tests - abnormal renal function tests Radiology: - MRI with contrast [1] - imaging can support diagnosis, but should not delay surgery [1] Differential diagnosis: - cellulitis Management: - surgical debridement within 24 hours - empiric antibiotic coverage: a) coverage for: 1] Staphylococcus aureus (including MRSA) 2] Streptococci - group-A beta-hemolytic Streptococci 3] anaerobes 4] gram negative rods b) vancomycin, linezolid or daptomycin plus - pipericillin tazobactam - imipenem or meropenem - metronidazole + cetriaxone or a fluoroquinolone [1]

Related

gas gangrene (anaerobic cellulitis)

General

fasciitis

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2006, 2009, 2012, 2015, 2018, 2021.
  2. Bingol-Kologlu M et al, Necrotizing fasciitis in children: Diagnostic and therapeutic aspects. J Pediatr Surg 2007 42:1892 PMID: 18022442
  3. Anaya DA, Dellinger EP. Necrotizing soft-tissue infection: diagnosis and management. Clin Infect Dis. 2007 Mar 1;44(5):705-10. Epub 2007 Jan 22. PMID: 17278065
  4. Wong CH, Khin LW, Heng KS, Tan KC, Low CO. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med. 2004 Jul;32(7):1535-41 PMID: 15241098
  5. Edlich RF, Bronze MS (images) Medscape: Necrotizing Fasciitis http://emedicine.medscape.com/article/2051157-overview
  6. DermNet NZ. Necrotising fasciitis (images) http://www.dermnetnz.org/bacterial/necrotising-fasciitis.html
  7. Stevens DL, Bryant AE. Necrotizing Soft-Tissue Infections. N Engl J Med 2017; 377:2253-2265. December 7, 2017 PMID: 29211672 http://www.nejm.org/doi/full/10.1056/NEJMra1600673