Cauda equina syndrome

Question 1

Anatomy of the cauda equina

Answer 1

It is a collection of nerve roots that travel through the spinal canal after the spinal cord terminates at L2/3

Tapers into the conus medullaris

Question 2

Function of the cauda equina

Answer 2

The nerves of the cauda equina supply:

• Sensation to the perineum, bladder and rectum
• Motor innervation to the lower limbs and the anal and urethral sphincters
• Parasympathetic innervation of the bladder and rectum

Question 3

What is cauda equina syndrome?

Answer 3

Compression of the nerves of the cauda equina

Question 4

What can cause cauda equina syndrome?

Answer 4

Herniated disc (the most common cause)
Tumours, particularly metastasis
Spondylolisthesis (anterior displacement of a vertebra out of line with the one below)
Abscess (infection)
Trauma

Question 5

What are the red flag symptoms seen in cauda equina syndrome?

Answer 5

Saddle anaesthesia (loss of sensation in the perineum – around the genitals and anus)

Loss of sensation in the bladder and rectum (not knowing when they are full)

Urinary retention or incontinence

Faecal incontinence

Bilateral sciatica

Bilateral or severe motor weakness in the legs

Reduced anal tone on PR examination

Question 6

Management of cauda equina

Answer 6

Immediate hospital admission

Emergency MRI scan to confirm or exclude cauda equina syndrome

Neurosurgical input to consider lumbar decompression surgery - should be done ASAP

Question 7

Complications of cauda equina

Answer 7

Even with early surgery, patients can be left with bladder, bowel or sexual dysfunction.

Leg weakness and sensory impairment can also persist.

Question 8

Presentation of metastatic spinal cord compression

Answer 8

Spinal cord is compressed

Presents similarly to CES:

• Back pain
• Motor and sensory signs/Sx
• Back pain is worse on coughing/straining

Presents with UMN signs (as opposed to LMN signs in CES)

Question 9

Management of Metastatic Spinal Cord Compression

Answer 9

It is an oncological emergency

Rapid imaging and treatment e.g.

• High dose dexamethasone (to reduce swelling in the tumour and relieve compression)
• Analgesia
• Surgery
• Radiotherapy
• Chemotherapy