A 62-year-old man with known prostate cancer presents with a 2-week history of progressive back pain, bilateral leg weakness, and difficulty passing urine for 3 days. He reports his legs feel "heavy" and numb below the knees.
Examination: Power 3/5 bilaterally in lower limbs, increased tone, brisk reflexes, bilateral extensor plantar responses. Reduced sensation below T10 level. Palpable bladder.
What is the diagnosis? What do you do in the next 30 minutes?
Understanding Spinal Cord Compression
Spinal cord compression (SCC) occurs when the spinal cord or cauda equina is compressed by an external mass — tumour, disc, haematoma, abscess, or fractured bone. It is a neurosurgical emergency — neurological function lost before decompression is often permanent, while function present at the time of surgery is usually preserved.
The most important principle: "Time is spine." Every hour of delay reduces the chance of neurological recovery.
Any patient with known malignancy who develops back pain + neurological symptoms has metastatic spinal cord compression until proven otherwise. This is a same-day emergency — MRI spine within 4 hours, steroids immediately, neurosurgical referral urgently.
Causes
| Cause | Key Features | Most Common Level |
|---|---|---|
| Metastatic tumour | Most common in adults — breast, prostate, lung, renal, myeloma | Thoracic (70%) |
| Disc prolapse | Younger patients, acute onset, often follows exertion | Lumbar (L4/5, L5/S1) |
| Spinal epidural abscess | Fever, back pain, risk factors (IV drug use, diabetes, immunosuppression) | Any level |
| Spinal epidural haematoma | Anticoagulation, trauma, spinal procedure | Any level |
| Primary spinal tumour | Slower onset, younger patients, meningioma/ependymoma most common | Thoracic |
| Vertebral fracture | Trauma or osteoporotic collapse, often sudden onset | Thoracolumbar junction |
Clinical Features — Know These Patterns
Clinical Syndrome by Level
- Cervical cord compression: Weakness in all four limbs (tetraparesis/tetraplegia), increased tone and reflexes, Lhermitte's sign (electric shock down spine on neck flexion), respiratory compromise if C3–C5 involved.
- Thoracic cord compression: Spastic paraparesis (UMN signs in legs), sensory level on trunk, bladder/bowel dysfunction. Most common site for metastatic SCC.
- Lumbar cord/Conus medullaris: Mixed UMN and LMN signs, saddle anaesthesia, early bladder/bowel involvement.
- Cauda equina syndrome: LMN flaccid weakness, saddle anaesthesia, urinary retention with overflow incontinence, loss of anal tone. Surgical emergency — decompress within 48 hours.
The triad of saddle anaesthesia + urinary retention + bilateral leg weakness = cauda equina syndrome. Ask about it in every back pain patient. Missing it means permanent incontinence and paralysis. Surgical decompression within 48 hours (ideally 24) gives the best outcomes.
Investigation
MRI whole spine with gadolinium is the investigation of choice — image the entire spine, not just the symptomatic level, as 10% of patients have multiple levels of compression. Do it same-day for any suspected SCC.
If MRI is unavailable: CT myelogram is an alternative. Plain X-rays are insufficient — normal X-ray does not exclude cord compression.
Bloods: FBC, U&E, CRP, PSA (if prostate cancer suspected), serum protein electrophoresis (myeloma), bone profile (hypercalcaemia of malignancy).
Management
Immediate Management
- Dexamethasone 16mg IV stat — reduces oedema around the compressed cord, can improve neurological function within hours. Start before imaging if clinical suspicion is high.
- Catheterise — urinary retention is common and causes additional distress. Insert urethral catheter immediately.
- Analgesia — adequate pain control is essential and humane.
- Urgent MRI spine — within 4 hours for suspected malignant SCC, immediately for acute traumatic or haematoma compression.
- Neurosurgical referral — same-day. Surgery indicated for: single level compression in good surgical candidate, radioresistant tumour, spinal instability, diagnostic uncertainty.
- Radiotherapy — for radiosensitive tumours (myeloma, lymphoma, breast, prostate) in patients unfit for surgery or with multilevel disease.
Prognosis
The single most important prognostic factor is neurological status at time of treatment. Patients who are ambulant when treated have a 90% chance of remaining ambulant. Non-ambulant patients have only a 30–50% chance of walking again after surgery. This is why early recognition matters so profoundly.
Metastatic spinal cord compression from prostate cancer at T10. Dexamethasone 16mg IV given immediately, urethral catheter inserted. MRI confirmed T10 vertebral metastasis with epidural extension compressing the cord. PSA markedly elevated. Neurosurgery reviewed — spinal stability assessment (SINS score) indicated surgical instability. He underwent T9–T11 decompression and stabilisation within 12 hours. Post-operatively received radiotherapy and hormonal therapy. He regained the ability to walk with a frame — a good outcome given his pre-treatment deficit.
Time is spine — every hour matters. Known malignancy + back pain + neurology = urgent MRI same day. Start dexamethasone 16mg IV immediately. Cauda equina syndrome = saddle anaesthesia + urinary retention + leg weakness — surgical emergency within 48 hours. Ambulant patients at treatment have 90% chance of staying ambulant. Neurological status at time of treatment is the strongest prognostic factor.
References
- Loblaw DA et al. Systematic review of the diagnosis and management of malignant extradural spinal cord compression. Journal of Clinical Oncology. 2005;23(9):2028–2037.
- Cahill KS et al. Prevalence, complications, and hospital charges associated with use of bone-morphogenetic proteins in spinal fusion procedures. JAMA. 2009;302(1):58–66.
- Todd NV. Guidelines for cauda equina syndrome. British Journal of Neurosurgery. 2009;23(1):3–7.
