title: A simple model to help distinguish necrotizing fasciitis from nonnecrotizing soft tissue infection.
abstract: BACKGROUND
  Necrotizing fasciitis (NF) has been associated with certain "hard" clinical signs (hypotension, crepitance, skin necrosis, bullae, and gas on x-ray), but these may not always be present. Using results of a previous study, we developed a simple model to serve as an adjunctive tool in diagnosing NF (admission WBC > 15.4 x 10(9)/L or serum sodium [Na] < 135 mmol/L) and determined its ability to distinguish between patients with NF and nonnecrotizing soft tissue infection (non-NF).
  
  
  METHODS
  A retrospective review was conducted of consecutive NF (n=31) and non-NF patients (n= 328) treated at a single institution during an 11-month period. Comparison of admission vital signs, physical examination findings, radiology results, and number of patients meeting model criteria was performed.
  
  
  RESULTS
  Ninety percent of NF patients and 24% of non-NF patients met model criteria (p < 0.0001). The model had a sensitivity of 90%, a specificity of 76%, a positive predictive value of 26%, and a negative predictive value of 99% for diagnosing NF. Nineteen (61%) NF patients had no "hard" signs of NF; the model correctly classified 18 (95%) of these patients.
  
  
  CONCLUSIONS
  Admission WBC greater than 15.4 x 10(9)/L and serum Na less than 135mmol/L are useful parameters that may help to distinguish NF from non-NF infection, particularly when classic "hard" signs of NF are absent.
authors.affiliation: Department of Surgery, Harbor-UCLA Medical Center, Torrance, CA 90509, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Wall
authors.forename: S R
authors.initials: SR
authors.lastname: Klein
authors.forename: S
authors.initials: S
authors.lastname: Black
authors.forename: C
authors.initials: C
authors.lastname: de Virgilio
mesh_terms: D000328:Adult; D003663:Decision Trees; D019115:Fasciitis, Necrotizing / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012964:Sodium / Q000097:blood; D018461:Soft Tissue Infections / Q000175:diagnosis*
chemical_list: D012964:Sodium