Back pain — suspected cauda equina syndrome

PLAB 2 & PRES 3 · msk · hard · 8 minutes

Candidate brief

You are an FY2 doctor/SHO in the Emergency Department. Mr Andrew Collins, 43, has severe lower-back pain radiating into both legs. Since this morning, he has also developed difficulty passing urine. Assess him, explain your concerns and initiate appropriate management. Verbalise any examinations, investigations, treatments and escalation steps you would undertake.

What examiners look for

Cauda equina syndrome is a time-critical spinal emergency caused by compression of the lumbosacral nerve roots. Ask directly and sensitively about: Difficulty starting or controlling urination. Loss of bladder-filling or urinary-flow sensation. Retention or new overflow leakage. Loss of bowel sensation or control. Saddle, perianal or genital numbness. New sexual dysfunction. Bilateral or progressive leg pain, weakness or numbness. Do not wait for complete urinary retention or incontinence. Earlier sensory or urinary changes may represent evolving CES. Perform and document a focused lower-limb and saddle-area neurological examination. Obtain consent, privacy and a chaperone before an intimate examination. A bladder scan is an adjunct. A post-void residual above 200 mL increases concern, but a lower result does not safely exclude CES. Active red flags require emergency MRI as soon as possible. Routine X-ray cannot exclude nerve-root compression. Keep the patient nil by mouth when surgery may be required and complete investigations without delaying MRI. MRI-confirmed CES requires emergent spinal or neurosurgical referral and careful documentation of all symptom, assessment, imaging, referral and transfer times.

Guideline references

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