Necrotising fasciitis — recognition and immediate management of a red, painful leg

Diagnosis: necrotising fasciitis with septic shock. The combination of severe pain out of proportion to the visible skin change, systemic toxicity (confusion, fever, tachycardia, hypotension), and cutaneous necrosis (dusky skin), haemorrhagic bullae and crepitus is the classical clinical picture of necrotising soft-tissue infection with gas-forming organisms. This is a surgical emergency — surgical exploration and debridement are both diagnostic and therapeutic.^[1][2]

Risk-stratify with the LRINEC score (high in this patient).^[3]

• CRP over 150 (4) + WBC over 25 (2) + Hb 110 (1) + Na under 135 (2) + creatinine over 141 (2) + glucose over 10 (1) = 12 / 13 — high risk.
• A score of 6 or above mandates urgent surgical assessment. Critically, a low score never overrides a clinically suspicious picture — do not delay surgery for a low score or for further imaging.

Immediate resuscitation — Surviving Sepsis hour-1 bundle.^[1]

• ABCDE; high-flow oxygen; two large-bore cannulae.
• Blood cultures, lactate, hourly urine output (catheter).
• Broad-spectrum IV antibiotics immediately (within 1 hour of septic shock).
• Balanced crystalloid 30 mL/kg bolus, titrated to perfusion; noradrenaline for fluid-refractory shock.
• Correct hyperglycaemia; do not delay surgery for fluid resuscitation to be complete.

Definitive management — urgent surgical exploration and debridement.^[1][2]

• The single most important determinant of survival is early, aggressive surgical debridement of all necrotic tissue (fascia, subcutaneous fat, skin as required), with a planned return to theatre every 24 to 48 hours until no further necrosis is found.
• Do NOT delay surgery for CT/MRI — imaging may help if the diagnosis is unclear and the patient is stable, but the finger test (grey dishwater fluid, lack of bleeding, friable fascia that dissects easily) at exploration is diagnostic.

Empirical antibiotic regimen (broad spectrum + toxin suppression).^[1]

• Carbapenem (meropenem) OR piperacillin-tazobactam PLUS clindamycin (suppresses bacterial toxin synthesis — important in GAS and staphylococcal toxic shock) PLUS vancomycin or linezolid for MRSA cover.
• Continue and de-escalate once cultures and histology return; the role of IV immunoglobulin is controversial but considered in streptococcal toxic-shock-like syndrome with refractory shock.
• Hyperbaric oxygen is adjunctive where available, never a substitute for surgery.