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Suspected incomplete cauda equina syndrome — MRCEM SBA MCQ

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HardNeurological emergenciesSuspected incomplete cauda equina syndromeMRCEM SBA

A 42-year-old man attends the emergency department with three weeks of low back pain radiating down his right leg. Over the past two days, the pain has spread to his left leg. Since this morning, he has had difficulty starting to pass urine, reduced awareness of urinary flow and altered sensation when wiping after opening his bowels. Examination confirms reduced perianal sensation, but leg power is preserved. He passes urine in the department; his post-void residual is 85 mL. He has no history of cancer, fever or recent spinal procedure. Emergency MRI is available on site, he has no MRI contraindication, and a senior emergency physician has reviewed him. What is the most appropriate management plan?

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

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Correct answer: D — Request emergency lumbar MRI now; keep him nil by mouth and refer for surgery if compression is confirmed.

The new difficulty initiating micturition, impaired sensation of urinary flow and perianal sensory change alongside back and radicular pain constitute suspected cauda equina syndrome. Preserved leg power and the ability to void do not remove that concern. Crucially, a post-void residual below 200 mL cannot be used to rule it out or defer imaging. The national pathway calls for emergency MRI as soon as possible, with the patient kept nil by mouth in case emergency surgery is needed; confirmed compression warrants immediate spinal surgical referral. ([gloshospitals.nhs.uk](https://www.gloshospitals.nhs.uk/media/documents/GIRFT_CES_Guidelines_2023_EJRRVj5.pdf)) A is attractive because spinal surgery may ultimately be required, but waiting for specialist approval before requesting an available MRI can introduce unnecessary delay. B mistakes a residual above 200 mL, which increases suspicion, for a required threshold. C would under-triage new bladder and perianal symptoms; an outpatient pathway may be appropriate for radicular pain without recent cauda equina symptoms. E would be appropriate if emergency MRI could not be provided locally, but this hospital can scan him now. ([gloshospitals.nhs.uk](https://www.gloshospitals.nhs.uk/media/documents/GIRFT_CES_Guidelines_2023_EJRRVj5.pdf))

Reference: NICE NG127: Suspected neurological conditions—recommendations for adults aged over 16 (2019) — https://www.nice.org.uk/guidance/ng127/chapter/recommendations-for-adults-aged-over-16 GIRFT National Suspected Cauda Equina Syndrome Pathway (2023) — https://www.gloshospitals.nhs.uk/media/documents/GIRFT_CES_Guidelines_2023_EJRRVj5.pdf Royal Cornwall Hospitals NHS Trust: Emergency Department Cauda Equina Syndrome Pathway Clinical Guideline (March 2024) — https://doclibrary-rcht.cornwall.nhs.uk/DocumentsLibrary/RoyalCornwallHospitalsTrust/Clinical/EmergencyDepartment/EmergencyDepartmentCaudaEquinaSyndromePathwayClinicalGuideline.pdf