Cauda equina syndrome

Disease class: Nerve compression syndromes
Disease class: Polyradiculoneuropathy

This is a well-known neurosurgical emergency. Prompt treatment can prevent permanent nerve damage and disability.

Pathophysiology

The spinal cord usually terminates at the level of lumbar vertebrae L1 and L2. Below this, the nerve tracts emerge as a bundle of spinal nerve roots. This is called the cauda equina (horse's tail). It consists of lumbar nerve pairs L2-L5, sacral nerve pairs S1-S5, and the coccygeal nerve pair. 

In cauda equina syndrome there is compression of these nerves. 
It is a polyradiculoneuropathy (polyneuropathy and polyradiculopathy). This means that multiple spinal nerve roots are compressed, affecting multiple nerves and multiple limbs.

• Radiculopathy: disease affecting spinal nerve roots
• Neuropathy: disease affecting nerves
• Mononeuropathy: disease affecting a single nerve
• Polyneuropathy: disease causing generalised nerve damage

 

Symptoms

• Weakness of the legs
• Numbness or Paraesthesia in the legs
• Numbness or Paraesthesia in the anogenital region
• Urinary retention
• Overflow incontinence
• Faecal incontinence
• Constipation
• Erectile dysfunction

 

Signs

• Saddle anaesthesia: Absent sensation over the anogenital and perineal region, as if sitting on an anaesthetising saddle.
• Bilateral motor neuropathy
• Bilateral sensory neuropathy
• Reduced anal sphincter tone 
• Absent anal reflex