Idiopathic Necrotizing

Early recognition and treatment of necrotizing fasciitis (NF) is essential for survival. Idiopathic NF occurs in the absence of a known causative factor or portal of entry for bacteria, so it may not be considered immediately when patients are admitted. This study aimed to identify specific features of idiopathic NF that are important for early recognition and to assess factors associated with mortality. The records of 185 patients with surgically confirmed necrotizing fasciitis between January 1998 and June 2006 were retrospectively reviewed. The infection was classified as either idiopathic or secondary NF, and the clinical presentation, etiology, predisposing factors, microbiology, and outcome of the two groups were compared. Idiopathic NF occurred in 115 of 185 patients (62.2%). Patients with idiopathic NF were more like than those with secondary NF to have diabetes mellitus or chronic renal insufficiency, and they were less likely to have fever or skin bullae. Significant predictors of death in patients with idiopathic NF were shock on admission, impaired renal function, and elevated aspartate aminotransferase. Mortality did not differ significantly between idiopathic and secondary NF. Idiopathic NF should be considered as a cause of unexplained soft tissue pain and tenderness, even in the absence of typical signs of this infection. ( J Intern Med Taiwan 2008; 19: 337-345 )