Complicated Skin and Soft Tissue Infections

Necrotizing Skin and Soft Tissue Infections ÎDiagnosis: > Delays in diagnosis increase both the morbidity and the mortality rate (1C). > The presence of gas in soft tissues is specific for necrotizing infections and more sensitive than physical examination (1C). > Computed tomography and MRI improve the detection of soft tissue gas (1B). > Radiographic findings of tissue fluid and edema are neither sensitive nor specific for necrotizing infection (1C). > Clinical features strongly suggestive of necrotizing infection (1C): (1) pain disproportionate to the findings at physical examination (2) tense edema (3) bullae (4) skin ecchymosis/necrosis (5) cutaneous anesthesia (6) systemic toxicity (7) progression despite antibiotic therapy (2) serum sodium concentration <135 mmol/L (3) blood urea nitrogen (BUN) concentration >15 mg/dL /L > Laboratory values predictive of the presence of necrotizing infection (1C): (1) white blood cell (WBC) count >14×109 ÎTreatment > Early appropriate antibiotic coverage of inciting pathogens is indicated (1C). > Timely surgical debridement improves outcome (1C). ▶ Although no randomized or important non-randomized studies in NSTIs exist to direct therapy specifically, adequate surgical debridement of involved tissue is confirmed to improve the outcome (1C). ▶ Frequent re-evaluation or return to the operating room within 24 hours should be undertaken to ensure adequacy of debridement and lack of progression (1C). ▶ Empiric antibiotic therapy should be directed toward the likely pathogens (1C). The likely pathogens differ depending on the clinical setting, inciting pathophysiology, and previous exposure to antibiotics (1C). ▶ Necrotizing infections are more frequently polymicrobial and may involve aerobic and anaerobic gram-positive and gram-negative pathogens (1C). ▶ Assuming that relevant pathogens are covered appropriately, several single-agent regimens probably are effective, including imipenem/cilastatin, meropenem, ertapenem, piperacillin/tazobactam, ticarcillin/clavulanic acid, tigecycline, and minocycline (2C). ▶ Increasing resistance of gram-negative bacilli to ampicillin/sulbactam raises concern about the use of this agent unless local sensitivities are known (1C). ▶ Numerous combinations of agents probably are equally effective in the treatment of NSTIs provided appropriate coverage of relevant pathogens is ensured (2C). Rapidly Progressive Soft Tissue Infections ÎMore rapidly progressive soft tissue infections can be caused by a variety of virulent pathogens characterized by significant toxin production including: > S. pyogenes, Clostridial species, CA-MRSA, Vibrio and Aeromonas spp., and S. aureus species that produce toxic shock syndrome toxin 1 (TSST-1). ÎAll these infections require early and aggressive antibiotic therapy and surgical debridement and drainage (1C). ÎCombination therapy that includes protein synthesis inhibitory agents to which the organism is sensitive should be provided (1C). > For gram-positive pathogens (S. pyogenes, Clostridial spp., Staph) – clindamycin, linezolid, or possibly erythromycin may be considered. > For gram-negative pathogens (Vibrio and Aeromonas spp.) – a member of the tetracycline class should be considered.

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