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Cauda equina syndrome — SCE Acute Medicine MCQ

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ModerateAcute Neurological PresentationsCauda equina syndromeSCE Acute Medicine

A 49-year-old man is assessed on the acute medical unit. He has severe back pain, bilateral sciatica and new urinary retention. Examination shows saddle sensory loss. Initial assessment includes relevant observations, bedside tests and urgent blood results. What is the most appropriate investigation?

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

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Correct answer: A — Urgent MRI lumbosacral spine

Urgent MRI lumbosacral spine is the best answer because red-flag symptoms suggest cauda equina compression needing urgent MRI and surgical pathway. Bedside ultrasound for pleural fluid is plausible, but it is less appropriate for the physiology or timing described in this stem. The other distractors either fit a neighbouring presentation, delay definitive treatment, or miss the key immediate risk. Clinical pearl: Urinary retention is a late and serious feature.

Reference: NICE CKS back pain; GIRFT spinal guidance