Necrotizing soft tissue infections

Abstract

Necrotising soft tissue infection (NSTI) presents unique challenges in diagnosis and management. The key to a successful outcome is a high index of suspicion in appropriate clinical settings. Type II NSTI tends to occur on an extremity in younger, healthier patients with a history of known trauma, and to be monomicrobial. Type I NSTI tends to occur on the trunk of older, less healthy patients without an obvious history of trauma, and tends to be polymicrobial. Other, rarer types exist as well. The pathophysiology of both types involves superantigen acticivty, as well as a number of microbial byproducts which collectively decrease the viscosity of pus, facilitating its spread along deep tissue planes and ultimately causing diffuse deep thrombosis and aggressive systemic sepsis. The most important physical finding is tenderness to palpation beyond the area of redness, and the lack of crepitus should not be seen as a reassuring sign. Suspected cases should undergo early surgical exploration for diagnosis, which may be performed at bedside through a small incision. Most imaging techniques are not sufficiently specific to warrant a delay in surgical exploration. The Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) shows promise as a tool for excluding suspected cases. Successful outcomes in cases of NSTI require early and aggressive serial debridement and a multidisciplinary critical care approach.

Keywords: Necrotising soft tissue infection; superantigen.