What is the Fournier Gangrene Severity Index (FGSI) and how is it used to predict mortality risk?

Updated: Jun 03, 2021
  • Author: Vernon M Pais, Jr, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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In 1995, Laor and colleagues introduced the Fournier Gangrene Severity Index (FGSI). [44] The FGSI is based on deviation from reference ranges of the following clinical parameters:

  • Temperature
  • Heart rate
  • Respiratory rate
  • White blood cell count (WBC)
  • Hematocrit
  • Serum sodium
  • Serum potassium
  • Serum creatinine
  • Serum bicarbonate

Each parameter is assigned a score between 0 and 4, with the higher values indicating greater deviation from normal. The FGSI represents the sum of all the parameters’ values.

Laor and colleagues determined that an FGSI greater than 9 correlated with increased mortality. [44] The FGSI has been validated in several retrospective studies. [45, 46, 47] In a retrospective review of 20 patients with Fournier gangrene, the average FGSI was 9 overall and 14 for fatal cases. An increased FGSI was predictive of having an increased mortality rate or hospital stay longer than the median (>25 days) (P=0.0194). [48]

In 2010, Yilmazlar and colleagues updated the FGSI (UFGSI), adding two additional parameters—age and extent of disease—to further refine the prognostic utility of the FGSI. [49]

These two groups concluded that the mortality risk in general may be directly proportional to the age of the patient and the extent of disease burden and systemic toxicity upon admission. Factors associated with an improved prognosis included the following [49, 50, 51] :

  • Age younger than 60 years
  • Localized clinical disease
  • Absence of systemic toxicity (eg, low FGSI)
  • Sterile blood cultures

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