Necrotizing Fasciitis

Epidemiology

Necrotizing fasciitis describes a severe and potentially life-threatening soft tissue infection usually caused by Streptococcus (beta-hemolytic Streptococcus ) or mixed bacterial flora. There are several types of bacterial soft tissue infections. Erysipelas involves the more superficial layers of the skin and cutaneous lymphatic vessels. A cellulitis is a bacterial infection that extends more deeply into the subcutaneous tissue but spares the fascia. Necrotizing fasciitis indicates destruction of the fascia or fat with or without skin or muscle necrosis. Myositis/ myonecrosis describes bacterial involvement of the underlying muscle.

In the past, different aspects of the disease spectrum have been described by different terms. These terms include nonclostridial gangrene, synergistic necrotizing cellulitis, and acute hemolytic streptococcal gangrene.

Necrotizing fasciitis is uncommon and typically affects elderly or immunocompromised patients. However the incidence appears to be increasing in young, healthy patients with an intact immune response. Common sites of origin include odontogenic, tonsillar, or pharyngeal infections or a prior history of surgery or radiation therapy.

Clinical Features

The initial findings are nonspecific and consist of fever, regional neck swelling, and erythema. The disease course is then characterized by the rapid onset of sepsis and associated complications that include septic shock and multisystem organ failure. The disease may extend inferiorly and result in a mediastinitis. The reported mortality rate is up to 75% of affected individuals.