A Review of Necrotizing Fasciitis and the Utility of the Laboratory Risk Indicator for Necrotizing Fasciitis Score in its Early Diagnosis at a Rural Australian Hospital

Background: Necrotizing fasciitis is a life-threatening orthopaedic emergency. This paper is a retrospective review of confirmed cases of necrotizing fasciitis (NF) in a rural centre. The primary aim was to define the trends in incidence, microbiological profile, management and mortality. The secondary aim was to assess the accuracy of the LRINEC score as a tool to diagnose and distinguish NF from cellulitis and other non-necrotizing soft tissue infections (NNSTIs). Methods: A retrospective paper based, and computerized search of the medical records was undertaken to identify adult patients diagnosed with NF between January 2009 and January 2018 was conducted. An age matched control group was generated from a randomized sample of patients diagnosed with cellulitis over the same timeframe. LRINEC scores of the NF and control group were calculated and compared. Results: Forty-five patients with NF were identified. A decreasing trend in incidence was noted from 2011 (5.43 per 100000 per year) to 2016 (3.81 per 100000 per year), however 13 cases of necrotizing fasciitis presented in 2017 with an estimated incidence of 13.7 per 100000. The overall mortality of patients with NF was 15.6%. The genus Streptococcus was the most common isolate (47%) with Staphylococcus a close second (32.4%). The LRINEC score had a sensitivity of 61% and a specificity of 79% at a score of ≥ 6. Conclusion: LRINEC scores in isolation cannot be reliably used to distinguish between NF and NNSTIs. A high index of clinical suspicion and early surgical referral for surgical cut-down diagnosis is recommended.