Necrotising fasciitis

Necrotising fasciitis is a life-threatening subcutaneous soft-tissue infection that requires a high index of suspicion for diagnosis.

Infection may be polymicrobial in aetiology (type I) due to mixed anaerobic/facultative anaerobic organisms, or due to a single organism (type II), most commonly Streptococcus pyogenes, also called group A streptococcus.

Necrotising fasciitis should be suspected in any patient with a soft-tissue infection accompanied by prominent pain and/or anaesthesia over the infected area, or signs and symptoms of systemic toxicity.

Signs that raise suspicion for necrotising fasciitis include the presence of hypotension and/or elevated creatinine, elevated creatine kinase, elevated C-reactive protein (>124 nanomol/L [13 mg/L]), elevated white blood cell count with marked left shift, and/or low serum bicarbonate.

No laboratory or imaging studies, alone or in combination, are sufficiently sensitive and specific to definitively diagnose or rule out necrotising fasciitis.

An urgent surgical consultation should be obtained as soon as the diagnosis is suspected. Treatment should not be delayed while awaiting microbiological and imaging investigations.

Definitive treatment is surgical debridement, repeated as necessary. Antibiotic therapy is crucial, but is considered adjunctive to surgical management. Empirical antibiotics should cover major bacterial aetiological agents, and group A streptococcal toxin production that can accompany type II necrotising fasciitis.

Necrotising fasciitis is a life-threatening subcutaneous soft-tissue infection that may extend to the deep fascia, but not into the underlying muscle. The causal organisms may be aerobic, anaerobic, or mixed flora. Two main clinical forms exist. Type I necrotising fasciitis is a polymicrobial infection with an anaerobe such as Bacteroides or Peptostreptococcus and a facultative anaerobe such as certain Enterobacterales or non-group A streptococcus.[1]Hoadley DJ, Mark EJ. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 28-2002. A 35-year-old long-term traveler with a rapidly progressive soft-tissue infection. N Engl J Med. 2002 Sep 12;347(11):831-7. http://www.ncbi.nlm.nih.gov/pubmed/12226155?tool=bestpractice.com [2]Childers BJ, Potyondy LD, Nachreiner R, et al. Necrotizing fasciitis: a fourteen-year retrospective study of 163 consecutive patients. Am Surg. 2002 Feb;68(2):109-16. http://www.ncbi.nlm.nih.gov/pubmed/11842952?tool=bestpractice.com [3]Hasham S, Matteucci P, Stanley PR, et al. Necrotising fasciitis. BMJ. 2005 Apr 9;330(7495):830-3. [Erratum in: BMJ. 2005 May 14;330(7500):1143.] http://www.ncbi.nlm.nih.gov/pubmed/15817551?tool=bestpractice.com [4]Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA: Elsevier; 2015:1194-215.[5]Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. https://academic.oup.com/cid/article/59/2/e10/2895845 http://www.ncbi.nlm.nih.gov/pubmed/24973422?tool=bestpractice.com Type II necrotising fasciitis is most commonly a monomicrobial infection with Streptococcus pyogenes (group A streptococci).[1]Hoadley DJ, Mark EJ. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 28-2002. A 35-year-old long-term traveler with a rapidly progressive soft-tissue infection. N Engl J Med. 2002 Sep 12;347(11):831-7. http://www.ncbi.nlm.nih.gov/pubmed/12226155?tool=bestpractice.com [2]Childers BJ, Potyondy LD, Nachreiner R, et al. Necrotizing fasciitis: a fourteen-year retrospective study of 163 consecutive patients. Am Surg. 2002 Feb;68(2):109-16. http://www.ncbi.nlm.nih.gov/pubmed/11842952?tool=bestpractice.com [3]Hasham S, Matteucci P, Stanley PR, et al. Necrotising fasciitis. BMJ. 2005 Apr 9;330(7495):830-3. [Erratum in: BMJ. 2005 May 14;330(7500):1143.] http://www.ncbi.nlm.nih.gov/pubmed/15817551?tool=bestpractice.com [4]Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA: Elsevier; 2015:1194-215.[5]Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. https://academic.oup.com/cid/article/59/2/e10/2895845 http://www.ncbi.nlm.nih.gov/pubmed/24973422?tool=bestpractice.com [6]Bisno AL, Stevens DL. Streptococcal infections of skin and soft tissues. N Engl J Med. 1996 Jan 25;334(4):240-5. http://www.ncbi.nlm.nih.gov/pubmed/8532002?tool=bestpractice.com Other infectious aetiologies may rarely cause a monomicrobial necrotising infection that may be associated with specific exposures or risk factors (e.g., freshwater exposure associated with Aeromonas hydrophila, saltwater exposure or consumption of raw oysters associated with Vibrio vulnificus).