Spinal cord injury

Overview

•Spinal cord injury (SCI) - trauma or non-traumatic pathology causing motor, sensory, and autonomic dysfunction below the level of injury

•Cervical spine most commonly injured (50-60% of traumatic SCI); males ~80% of cases

•Cord extends to conus medullaris at L1-L2; below this = cauda equina (LMN lesion, not cord)

Presentation

•Neck/back pain at injury level - absence does not exclude SCI in unconscious or distracted patient

•Weakness - initially flaccid (spinal shock), then UMN pattern (spastic, hyperreflexic) once shock resolves

•Neurogenic shock - bradycardia + hypotension + warm peripheries; injuries at T6 and above; loss of sympathetic tone (distinct from hypovolaemic shock)

•Respiratory compromise - injuries above C3 risk apnoea (phrenic nerve C3-C5); C5 and above likely need ventilatory support

•Bladder/bowel dysfunction - neurogenic bladder, urinary retention, loss of sphincter control

Investigations

🥇 First-line

•CT spine (whole spine in high-energy trauma) - identifies bony injury, fractures, dislocations, canal compromise; faster and more sensitive than plain X-ray

🏆 Gold standard

•MRI spine - evaluates cord parenchyma, disc herniation, epidural haematoma, ligamentous injury, cord oedema; essential for neurological deficit

•ABG and spirometry - FVC <1L is indication for ventilatory support in cervical injuries

🎯

NEXUS criteria and Canadian C-spine Rule identify low-risk patients where imaging can be deferred. In high-energy trauma or any neurological signs, proceed directly to CT.

Management

•Immobilise cervical spine; transfer to Major Trauma Centre then specialist spinal injuries unit

•Haemodynamic optimisation - target MAP 85-90 mmHg with vasopressors in neurogenic shock

•Early surgical decompression where indicated

•Respiratory monitoring - consider non-invasive or invasive ventilation in cervical injuries

Complications

•Respiratory failure - most common cause of early death in cervical SCI

•VTE - DVT in up to 80% without prophylaxis; PE is leading cause of death in subacute phase; combined mechanical and pharmacological prophylaxis required

•Pressure injuries - reposition every 2 hours, specialist mattresses, skin surveillance

•Neurogenic bladder - managed with clean intermittent self-catheterisation (CISC) first-line

•Spasticity - baclofen (oral or intrathecal) or botulinum toxin injections

•Neuropathic pain - gabapentin or amitriptyline first-line

Prognosis

•Prognosis determined by ASIA grade and neurological level at 72 hours (after spinal shock resolves)

•ASIA A (complete) - <5% chance of meaningful motor recovery below level of injury

•Brown-Séquard - best prognosis; >90% recover ambulatory function

•Sacral sparing at initial presentation = best single predictor of motor recovery

Tract anatomy - essential for incomplete syndromes

Key spinal cord tracts

Tract	Function	Decussation	Location
Corticospinal	Voluntary motor	Medulla	Lateral/anterior white matter
Spinothalamic	Pain and temperature	1-2 segments of entry (anterior commissure)	Anterolateral cord
Dorsal columns	Fine touch, vibration, proprioception	Medulla (ipsilateral until then)	Posterior cord

💡

Sacral sparing - sacral fibres lie most peripherally and may be preserved in central/incomplete injuries. Preserved perianal sensation or anal tone = incomplete injury and best single predictor of motor recovery.

Incomplete cord syndromes

Autonomic dysreflexia - emergency

🚨

Medical emergency in SCI at T6 and above. Uncontrolled sympathetic response to stimulus below injury. Features: sudden severe hypertension, bradycardia, flushing above lesion, pallor below, pounding headache, sweating. Most common triggers: blocked catheter or faecal impaction.

Step 1

1. 1Sit patient upright immediately - lowers BP by pooling blood

↓

Step 2

1. 1Check urinary catheter - straighten or replace if blocked/kinked

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Step 3

1. 1Check for faecal impaction - apply topical anaesthetic gel before digital removal

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Step 4

1. 1Monitor BP every 5 minutes

↓

SBP remains >150 mmHg after trigger removed

Sublingual GTN 400 micrograms or nifedipine 10 mg

Refractory

IV labetalol or hydralazine + urgent senior review