Synopsis
Identify evolving sacral nerve and terminal cord dysfunction, use a low threshold for emergency MRI and coordinate decompression without relying on any single symptom, examination or bladder volume.
- Cauda equina syndrome is dysfunction from compression of multiple lumbosacral nerve roots below the cord; a large central disc is common, but tumour, abscess, haematoma, stenosis and trauma also cause it.
- Conus medullaris syndrome affects the terminal spinal cord around L1 and often produces more symmetrical deficits, early severe bladder or bowel dysfunction, saddle loss and mixed upper- and lower-motor-neurone signs.
- Early urinary clues are difficulty initiating micturition, impaired awareness of flow or bladder filling, reduced urge and altered urethral sensation; painless overflow retention is a late feature.
Key red flags
Back or bilateral radicular pain accompanies altered urinary sensation, impaired initiation, need to strain or reduced stream awareness while voluntary voiding remains possible, often with saddle change.
Investigation priorities
Confirm or exclude compression of the cauda equina or conus and define disc, tumour, infection, blood or stenosis for surgery.
Management branches
New back or radicular pain accompanies any credible bladder, bowel, sexual, saddle or severe bilateral motor red flag.
- Record the onset and evolution of urinary initiation, flow sensation, filling awareness, saddle and genital sensation, rectal fullness, sexual function and leg symptoms using clear non-leading language.
- Perform a focused neurological and consented sacral examination, scan the bladder after voiding when feasible and provide analgesia without allowing normal tone or low residual to overrule the syndrome.
Key medicines
AnalgesiaTitrate a local acute back-pain regimen while preserving consciousness and the ability to repeat examination.
Urinary catheterisationUse aseptic drainage for clinically significant retention with volume and timing documented in the record.