IDIOPATHIC NECROTIZING FASCIITIS - RECOGNITION, INCIDENCE, AND OUTCOME OF THERAPY

Early recognition and treatment of necrotizing fasciitis (NF) is essen tial for survival. The diagnosis of primary or idiopathic NF may be pa rticularly challenging because it occurs in the absence of a known cau sative factor or portal of entry for bacteria. Patients with NF treate d between 1989 and 1993 were reviewed to determine the incidence, clin ical features, bacteriology, and results of treatment in patients with idiopathic NF. Idiopathic NF occurred in nine (18%) of 51 patients, f ive men and four women, ranging in age from 21 to 67 years. Associated conditions included diabetes mellitus (4), alcoholism (3), remote inf ection (3), and pregnancy (2). NF affected the lower extremity in eigh t and the perineum in one patient. Pain and tenderness occurred in all patients, soft tissue gas was recognized in two, and the presence of erythema and edema was variable. Idiopathic NF was monomicrobial in se ven (78%) patients, compared to 21 per cent of patients with secondary NF (P = 0.003). S. pyogenes was the causative organism in five of sev en monomicrobial infections. Time from admission to operation was sign ificantly longer (62.3 +/- 54.8 hours) in patients with idiopathic NF compared to patients with secondary NF (17.0 +/- 16.6 hours) (P = 0.00 1). Treatment included operative debridement (xBAR = 3.3) and limb amp utation (n = 1) to control infection. Three patients (33%) with idiopa thic NF died. Primary or idiopathic NF is principally a monomicrobial infection usually caused by S. pyogenes that most commonly occurs in t he extremities. Mortality is high but is comparable to secondary NF. I t is important to recognize that NF may occur spontaneously, and it sh ould be suspected in patients with unexplained soft tissue pain and te nderness.