Necrotizing fasciitis: clinical presentation, microbiology, and determinants of mortality.

BACKGROUND: Necrotizing fasciitis is a life-threatening soft-tissue infection primarily involving the superficial fascia. The present report describes the clinical presentation and microbiological characteristics of this condition as well as the determinants of mortality associated with this uncommon surgical emergency. METHODS: The medical records of eighty-nine consecutive patients who had been admitted to our institution for necrotizing fasciitis from January 1997 to August 2002 were reviewed retrospectively. RESULTS: The paucity of cutaneous findings early in the course of the disease makes the diagnosis difficult, and only thirteen of the eighty-nine patients had a diagnosis of necrotizing fasciitis at the time of admission. Preadmission treatment with antibiotics modified the initial clinical picture and often masked the severity of the underlying infection. Polymicrobial synergistic infection was the most common cause (forty-eight patients; 53.9%), with streptococci and enterobacteriaceae being the most common isolates. Group-A streptococcus was the most common cause of monomicrobial necrotizing fasciitis. The most common associated comorbidity was diabetes mellitus (sixty-three patients; 70.8%). Advanced age, two or more associated comorbidities, and a delay in surgery of more than twenty-four hours adversely affected the outcome. Multivariate analysis showed that only a delay in surgery of more than twenty-four hours was correlated with increased mortality (p < 0.05; relative risk = 9.4). CONCLUSIONS: Early operative débridement was demonstrated to reduce mortality among patients with this condition. A high index of suspicion is important in view of the paucity of specific cutaneous findings early in the course of the disease.