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Suspected necrotising fasciitis with sepsis — MRCEM SBA MCQ

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HardInfection and sepsisSuspected necrotising fasciitis with sepsisMRCEM SBA

A 48-year-old man attends the emergency department 36 hours after a minor cut to his calf. He has rapidly worsening leg pain that extends well beyond a small area of erythema. There is a new dusky patch, but no crepitus. His temperature is 39.1°C, pulse 124/min, respiratory rate 28/min, blood pressure 88/52 mmHg and oxygen saturation 97% on air; he is alert. Venous lactate is 4.1 mmol/L. His reported LRINEC score is 2, and a plain radiograph shows no soft-tissue gas. Blood cultures have been taken and intravenous access established. He has no antibiotic allergy. The critical care team has been alerted, but treatment has not started. What is the most appropriate next management plan?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Start broad-spectrum intravenous antibiotics and fluid resuscitation; request immediate surgical assessment for exploration without awaiting CT.

Rapid progression after a skin break, pain extending beyond the visible erythema and dusky skin raise strong suspicion of necrotising soft-tissue infection. Hypotension and raised lactate also require immediate sepsis treatment. A low LRINEC score and absence of gas on a plain radiograph do not safely exclude the diagnosis. Start intravenous antibiotics selected according to local guidance, give reassessed crystalloid boluses and obtain urgent surgical assessment for exploration and debridement; CT must not delay surgical review. ([tsaco.bmj.com](https://tsaco.bmj.com/content/3/1/e000157?utm_source=openai)) B is tempting because CT may help define the extent of infection, but making surgical assessment conditional on CT risks delaying source control. C gives appropriate initial treatment but treats the low score and limited skin changes as grounds to observe rather than escalate. D gets the surgical priority right, but flucloxacillin alone is narrower than empirical treatment recommended for suspected necrotising infection. E appropriately recognises the need for critical care; that review should proceed alongside, not before, urgent surgical assessment. ([rightdecisions.scot.nhs.uk](https://www.rightdecisions.scot.nhs.uk/antimicrobial-prescribing-nhs-lothian/body-systems/skin-and-soft-tissue-infections/severe-soft-tissue-infection-including-suspected-necrotising-fasciitis-and-fourniers-gangrene/?utm_source=openai))

Reference: Antibiotic Therapy for Wound and Soft Tissue Infections including Necrotising Fasciitis, guideline 96FM.14 (Effective September 2026) — https://www.bucksformulary.nhs.uk/docs/guideline_96fm.pdf NHS Lothian: Severe soft tissue infection including suspected necrotising fasciitis and Fournier's gangrene (2024) — https://www.rightdecisions.scot.nhs.uk/antimicrobial-prescribing-nhs-lothian/body-systems/skin-and-soft-tissue-infections/severe-soft-tissue-infection-including-suspected-necrotising-fasciitis-and-fourniers-gangrene/ NICE NG253: Managing suspected sepsis (2025) — https://www.nice.org.uk/guidance/ng253/chapter/Managing-suspected-sepsis