Clinical Features of Spinal Cord Compression and Cauda Equina Syndrome
| Clinical feature | Comment | |
|---|---|---|
| Spinal pain | Almost all patients with cord compression due to malignant disease will have spinal pain, and pain is typically the first symptom. May be focal, radicular or referred. | |
| Site of compression | Around 70% of cases occur in the thoracic spine. The vast majority (>90%) are extradural; intramedullary (within the spinal cord) metastases are very rare. Thoracic pain following mild trauma may distract from the underlying diagnosis: trauma can precipitate a pathological fracture in pre-existing disease. | |
Around 75% of patients have limb weakness at the time of diagnosis Spasticity and hyperreflexia take time to develop, and may be absent in the acute setting. | ||
| Motor system | Site of compression | Type of weakness |
| Above C5 | Spastic quadraparesis: upper motor neuron (UMN) distribution with spasticity and brisk reflexes in all four limbs and extensor plantars | |
| Between C5 and T1 | Lower motor neuron (LMN) weakness at the level of the lesion (e.g. in the hands) and UMN weakness below | |
| Between T1 and L1 | Spastic paraparesis: UMN weakness in the lower limbs; upper limbs unaffected | |
| Below L1 | LMN weakness in the lower limbs | |
Sensory system See Figure18.2Sensory innervation of the skin | Site of compression | Sensory level |
| Above C5 | Neck | |
| Between C5 and T1 | Upper limbs | |
| Between T1 and T6 | Thorax | |
| Between T7 and T12 | Abdomen | |
| Below L1 | Lower limbs | |
| Sphincter disturbance | Abnormalities of bladder function almost always precede those of bowel function. Lesions at or above the conus medullaris (the termination of the spinal cord) lead to a reflex neurogenic, or ‘automatic’ bladder, with overactivity, urgency and incomplete emptying; this is an UMN lesion, best thought of as bladder spasticity. Bowel abnormalities present as constipation. Lesions compressing the cauda equina cause overflow urinary incontinence due to a loss of bladder motor function, so that the bladder passively fills; this is a LMN lesion, best thought of as bladder flaccidity. Bowel abnormalities present as loss of anal sphincter tone and faecal incontinence. There is perineal sensory loss – the classic ‘saddle anaesthesia’. | |