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KEY POINTS
Necrotizing soft tissue infections (NSTIs) are life-threatening soft tissue infections defined by a necrotizing component involving any or all the layers of the soft tissue compartment.
NSTIs of the extremities, mainly of the lower limb, represent the most common condition.
Most NSTIs involve polymicrobial pathogens; In 20% to 30% of cases, NSTIs are monomicrobials and primarily involve Group A streptococcus (GAS).
The “gold standard” to confirm the diagnosis of NSTI is surgical exploration.
In patients with sepsis or septic shock, imaging (CT scan and/or MRI) must never delay surgery.
The key early therapeutic interventions required are broad-spectrum antibiotics and debridement surgery.
The mainstem of empiric treatment is a broad-spectrum beta-lactam with additional aminoglycosides in case of septic shock. Clindamycin should be added in case of documented or suspected (GAS) infection.
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Soft tissue infections form a group of heterogeneous diseases, which include necrotizing (NSTIs) and non-necrotizing soft-tissue infections (non-NSTIs). While non-NSTIs include various entities that require antibiotic treatment (eg, cellulitis, erysipela) and sometimes surgical drainage (eg, skin abscess)1 but are rarely life-threatening, NSTIs always require not only early broad-spectrum antibiotics but also urgent surgical debridement of infected tissues. Intensive care unit (ICU) admission is also frequently required in the latter as organ failures are associated in approximately 50% of cases.2–4 NSTIs encompass all infections with a necrotizing component involving any or all the layers of the soft tissue compartment, from the dermis and subcutaneous tissue to the deeper fascia and muscle. Because most ICU patients admitted with skin and soft tissue infections are eventually diagnosed with NSTIs,5,6 the current article will be focused on aspects related to the practical management of patients with NSTIs in the ICU.
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Definitions, Classifications, and Epidemiology
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Multiple terms relating to NSTIs have been used in the literature, based on the historical nosology (eg, necrotizing fasciitis, hospital gangrene, Fournier’s gangrene, Meleney’s gangrene), microbiological categorizations (ie, types I, II, or III infections) or subtypes (eg, synergistic gangrene, clostridial cellulitis), the anatomical location (eg, lower/upper limbs, abdomino-perineal region) or the depth of infection (eg, cellulitis, fasciitis, myonecrosis).
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These classifications are often confusing and of little help to the clinician, except for the anatomical categorization (Table 77-1). In fact, the most important aspect in clinical practice is to distinguish non-NSTIs from NSTIs, because all NSTIs will require urgent surgical debridement.
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