Necrotizing Fasciitis

This polymicrobial infection, characterized by rapidly advancing deep tissue necrosis, is caused by Gram-positive and Gram-negative bacteria and anaerobes such as Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. About 10% of cases are caused by streptococci (primarily group A). Risk factors include a history of penetrating injuries, surgery, irradiation, malignancy, diabetes, alcoholism, or malnutrition. Minor skin infections, such as furuncles, are present in about 20% of patients in whom necrotizing fasciitis develops. Pain that is disproportionate to the clinical appearance of an eruption suggests the possibility of necrotizing fasciitis.

The recommended diagnostic procedure is to perform a wedge biopsy down to fascia. Fine-needle aspiration of fluid from subcutaneous tissue for Gram staining and frozen-section tissue biopsy can help establish the diagnosis. Cultures of surgical samples and blood help identify the relevant organisms. MRI can determine the site and depth of necrosis.

Treatment of suspected necrotizing fasciitis must be initiated immediately, because progression of the infection may result in shock and death. Treatment consists of antibiotics such as gentamicin and clindamycin to cover both aerobes and anaerobes, and swift and vigorous debridement of necrotic tissue. Supportive measures include proper nutrition, hydration, and monitoring.