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Immediately threatened acute lower limb ischaemia — MRCEM SBA MCQ

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HardCardiovascular emergenciesImmediately threatened acute lower limb ischaemiaMRCEM SBA

A 76-year-old man with atrial fibrillation, who is not taking anticoagulation, presents to a district general hospital two hours after sudden onset of severe left leg pain. The foot is pale and cold. There are no pedal arterial Doppler signals, but a venous signal is present. Sensation is reduced over the forefoot, and he can move his toes only weakly. The skin remains blanchable, with no fixed mottling. He has no active bleeding or contraindication to heparin. Intravenous access, analgesia and monitoring are in place. The regional vascular service can receive him immediately; the next local CT angiography slot is in 90 minutes. Which management plan is most appropriate?

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

Reveal the answer and explanation

Correct answer: D — Give intravenous unfractionated heparin and arrange immediate vascular transfer for emergency revascularisation.

The abrupt onset in a patient with atrial fibrillation suggests acute arterial embolism. More importantly, sensory loss **and new motor weakness** indicate an immediately threatened limb, rather than one suitable for observation. Preserved movement and blanchable skin argue against irreversible ischaemia. Give intravenous unfractionated heparin promptly, unless contraindicated, and arrange immediate vascular assessment and transfer for emergency revascularisation. The vascular team can determine the definitive technique; a 90-minute wait for local imaging must not postpone their assessment or limb-saving treatment. ([uhmeded.uhcw.nhs.uk](https://uhmeded.uhcw.nhs.uk/Portals/0/AssetUploads/postgraduate%20doctor%20handbook%20vascular%20surgery.pdf?ver=J31Xh9oBpW-pz7rUA76oDQ%3D%3D&utm_source=openai)) **A** delays transfer for imaging, although prompt imaging may help when it does not delay treatment. **B** mistakes evolving neurological deficit for a limb that can be monitored locally. **C** commits to a prolonged thrombolytic infusion when motor weakness makes rapid reperfusion the priority; catheter-directed treatment may be appropriate for a less immediately threatened limb following vascular assessment. **E** treats potentially reversible ischaemia as irreversible: profound paralysis, anaesthesia and fixed mottling would instead raise concern that revascularisation cannot salvage the limb. ([bmj.com](https://www.bmj.com/content/346/bmj.f2681/rr?utm_source=openai))

Reference: Postgraduate Doctor Handbook: Vascular Surgery — Acute Limb Ischaemia (2023) — https://uhmeded.uhcw.nhs.uk/Portals/0/AssetUploads/postgraduate%20doctor%20handbook%20vascular%20surgery.pdf?ver=J31Xh9oBpW-pz7rUA76oDQ%3D%3D Assessment and management of peripheral arterial disease: what every cardiologist should know (2021) — https://heart.bmj.com/content/heartjnl/early/2021/05/13/heartjnl-2019-316164.full.pdf Acute leg ischaemia: Can they wiggle their toes? (2013) — https://www.bmj.com/content/346/bmj.f2681/rr