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Soft tissue infections characterized by extensive necrosis of subcutaneous tissue, fascia, or muscle are uncommon, but they require prompt recognition and urgent surgical treatment.
The classic hallmarks of necrotizing soft tissue infections are extensive involvement of the subcutaneous tissues and a relative paucity of cutaneous involvement until late in the course of the infection.
Rapidly spreading soft tissue infections present acutely with severe systemic toxicity.
Successful management of these critically ill patients depends on prompt diagnosis by clinical and radiologic means.
The principles of management include fluid resuscitation, hemodynamic stabilization, a broad-spectrum antimicrobial regimen, and early surgical intervention.
Prompt surgery, in which a definitive diagnosis is reached and all necrotic tissue is debrided, should be considered the mainstay of treatment.
The mortality rate is highest when the diagnosis is delayed or initial surgical treatment is limited.
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CLASSIFICATION OF SOFT TISSUE INFECTIONS
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In severe soft tissue infections, the initial cutaneous presentation often belies the relentless progression of subcutaneous tissue necrosis and dissection that lies beneath a normal-appearing skin. Successful management of these soft tissue infections depends on early recognition, appropriate investigations to establish a specific diagnosis, and combined surgical and medical intervention. A clear understanding of a classification of these entities is required, but, unfortunately, the published literature in this area may be confusing because of a lack of uniformity in descriptive terminology and the use of different classification schemes. The confusion is compounded by the fact that certain clinical entities may involve one or more anatomic planes within the subcutaneous tissue, and one or more bacterial species may be responsible for the same or different clinical entities. Although classification schemes based on microbial etiology may be the most complete, they offer little to the clinical diagnostic process necessary to expedite appropriate management.1 To place a useful clinicoanatomic classification into perspective, a review of the basic anatomy and microbial ecology of the skin and subcutaneous tissues is necessary.
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ANATOMY AND MICROBIAL ECOLOGY OF THE SKIN AND SOFT TISSUES
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The skin consists of an outer layer, the epidermis, and an inner layer, the dermis, which resides on a fibrous connective tissue layer, the superficial fascia. Beneath this layer, the avascular deep fascia overlies and separates muscle groups and acts as a mechanical barrier against the spread of infections from superficial layers to the muscle compartments. Between the superficial and deep fascia lies the fascial cleft, which is mainly composed of adipose tissue and contains the superficial nerves, arteries, veins, and lymphatics that supply the skin and adipose tissue.
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Our understanding of the numbers and types of microbial species present on the skin has significantly changed with the use of 16S ribosomal RNA techniques, directly from their genetic material, compared to previous microbiological culture.2,3 This understanding will likely continue to evolve with additional work being conducted on the Human ...