🩸 Chapter 107: Severe Skin and Soft-Tissue Infections

Necrotizing fasciitis (NSTI) · Type 1 polymicrobial vs Type 2 GAS/MRSA · Fournier's gangrene · Surgical debridement · Empiric antibiotics · Hyperbaric oxygen · IVIG · Surgical site infections

🔍 Core Concepts: Severe SSTI (Necrotizing & Surgical Site)

📌 Necrotizing fasciitis (NSTI) types
Type 1: polymicrobial (Bacteroides, Enterobacteriaceae, enterococci). Type 2: Group A Strep ± S. aureus (including MRSA). Type 3: Clostridial (gas gangrene).
⚠️ Early signs (pain out of proportion, erythema, edema)
Late signs: hemorrhagic bullae, crepitus, dishwater discharge, necrosis, systemic toxicity. MRI is imaging of choice.
🔪 Surgical debridement is life-saving
Do not delay for hemodynamic stabilization. Excise all necrotic tissue until healthy bleeding edges. Re-explore within 24-48h.
💊 Empiric antibiotics
Type 1: carbapenem or pip-tazo + clindamycin. Type 2: penicillin G + clindamycin (GAS) ± vancomycin (MRSA). Add IVIG if toxic shock.
🩺 Surgical site infection (SSI)
Superficial (skin/subcutaneous), deep (fascia/muscle), organ/space. Risk: dirty wound, comorbidities, prolonged surgery. Treat with drainage + antibiotics (MSSA coverage).
🛡️ Supportive care
Fluid resuscitation, vasopressors for septic shock, nutritional support, early mobilization. HBO controversial, not routinely recommended.

🩺 Stepwise Management of Necrotizing Soft-Tissue Infection (NSTI)

1
Recognize early signs: high index of suspicion
Pain out of proportion to exam, rapid progression of erythema/edema, systemic toxicity (tachycardia, fever, hypotension). Late signs: bullae, crepitus, necrosis.
2
Immediate surgical consult + debridement
Do not delay for imaging or stabilization. Debride all necrotic fascia and muscle until bleeding healthy tissue. Amputation if necessary. Re-explore within 24-48h.
3
Broad-spectrum empiric antibiotics
Carbapenem or piperacillin-tazobactam + clindamycin (antitoxin effect) + vancomycin if MRSA risk. For suspected GAS: penicillin + clindamycin.
4
Resuscitation & organ support
Aggressive IV fluids, vasopressors (norepinephrine), early intubation if airway compromise or shock. Consider IVIG for streptococcal toxic shock.
5
Post-debridement wound care
Moist saline gauze dressing, avoid topical antimicrobials. Negative-pressure therapy may be used. Skin grafting after granulation.