Cauda equina syndrome

Question 1

Define cauda equina syndrome?

Answer 1

Rare form of spinal stenosis that is characterised by compression of multiple lumbar and sacral nerve roots of the cauda equina

Question 2

Define spinal stenosis?

Answer 2

Too little space inside backbone

Question 3

What spinal nerves, and their nerve roots, make up the cauda equina?

Answer 3

L2-L5
S1-S5
Coccygeal nerve

Question 4

What are the 2 main actions of the cauda equina?

Answer 4

Innervation of pelvic organs

Motor function of lower limbs

Question 5

Is cauda equina syndrome more common in men or women?

Answer 5

Equally common

Question 6

Is cauda equina syndrome more common in adults or children?

Answer 6

More common in adults

Question 7

What are the 2 most common causes of cauda equina syndrome in children?

Answer 7

Spinal injury

Spinal congenital abnormality

Question 8

What is the incidence of cauda equina syndrome in the general population?

Answer 8

1 in 65,000 people affected

Question 9

Which 2 factors determine the severity of symptoms of cauda equina syndrome?

Answer 9

Degree of nerve root compression

Which specific nerve roots are compressed

Question 10

What is the most common red flags symptom of CES, and why is it the most important symptom to identify?

Answer 10

Most common red flag symptom is urinary function

Degree of urinary function distinguishes between early/partial and late/complete CES

Question 11

What 4 sites make up the ‘saddle area’?

Answer 11

Perineum (area between anus and scrotum/vulva)

Anus

Genitals

Buttocks

Question 12

What are the 2 stages of CES?

Answer 12

Early/partial CES

Late/complete CES

Question 13

How is the saddle area affected in early CES compared to late CES?

Answer 13

Early CES: patient has altered sensation in saddle area

Late CES: patient has no sensation in saddle area

Question 14

How is ability to urinate affected in early CES compared to late CES?

Answer 14

Early CES: patient has less desire to urinate/void full bladder and produces small urine volume voluntarily

Late CES: patient has painless urinary retention (inability to voluntarily urinate/void full bladder) so produces no urine voluntarily and has overflow incontinence

Question 15

Why do patients with late CES have painless urinary retention?

Answer 15

They have no sensation in saddle area, so will not feel unpleasant feeling when they have a full bladder

Question 16

Why does urinary retention lead to overflow incontinence in late CES patients?

Answer 16

Patient is unable to voluntarily urinate due to loss of saddle area sensation, eventually bladder will fill capacity and overflow due to complete loss of bladder function

Question 17

How is the bladder function affected in early CES compared to late CES?

Answer 17

Early CES: patient still has some bladder function and control, might have stress incontinence

Late CES: patient has complete loss of bladder function and control, will have overflow incontinence

Question 18

Give 4 red flag symptoms of CES that don’t involve urinary function?

Answer 18

Sexual dysfunction (eg. women have painful intercourse, men have erectile dysfunction)

Weakness and paralysis in lower limbs

Faecal incontinence due to loss of function of anal sphincter muscles

Lower back pain

Question 19

Give 6 differential diagnosis of CES?

Answer 19

spinal metastasis, ankylosing spondylitis, discitis, osteoporotic compression fractures, sciatica, spondylosis

Question 20

Give 4 important symptoms that can be identified from patient history, in investigation of CES?

Answer 20

Has patient experienced sexual dysfunction such as painful intercourse, erectile dysfunction

Has patient had lower back pain

Has patient had numbness, pain in legs and feet

Has patient had urinary symptoms

Question 21

What 3 factors are tested in physical examination, for investigation of CES?

Answer 21

Sensation, muscle strength, reflexes

In legs and feet

Question 22

Give 3 findings of CES in a physical examination of lower limbs?

Answer 22

Diminished/no knee and ankle jerks

Negative babinski sign

Bilateral leg pain

Question 23

What is the plantar reflex test, and what are the normal and abnormal findings?

Answer 23

Plantar reflex test: Simulation lateral palmar aspect of foot causes movement of hallux (big toe)

Normal finding: hallux flexion, which is a negative babinski sign

Abnormal finding: hallux extension, which is a positive babinski sign

Question 24

Give 3 imaging mediums that can be used for radiological investigation of CES?

Answer 24

MRI

CT

Myelogram (Spinal canal X-ray)

Question 25

What is the ideal imaging medium for investigation of CES and why?

Answer 25

MRI imaging shows discs (CES commonly caused by large disc herniation in lower back) and nerve roots (soft tissues) so is the ideal imaging choice

Question 26

Why is MRI preferred over CT for investigation of CES?

Answer 26

CT imaging shows bony structures in more detail than x-ray but is inferior in soft-tissue imaging compared to MRI, so won’t show nerve roots and discs

Question 27

What is injected into the spinal canal when doing a myelogram for investigation of CES, and why?

Answer 27

Myelogram (Spinal canal X-ray) with injected contrasting fluid can show displacement of spinal cord due to herniated discs, bony spurs, tumours

Question 28

Give 2 reasons why CES is a medical emergency and should be managed urgently?

Answer 28

Prevent permanent paralysis

Prevent permanent loss of bladder and bowel control

Question 29

What kind of surgery is performed to manage CES, and give 2 types?

Answer 29

Emergency decompression surgery within 24 hours

eg. Lumbar laminectomy

eg. Discectomy

Question 30

How is a lumbar laminectomy performed to treat CES?

Answer 30

Part of the lamina which has grown bony spurs and is compressing nerve root is removed

Question 31

How is a discectomy performed to treat CES?

Answer 31

Part of herniated disc which is compressing nerve root is removed

Question 32

Give 3 examples of medications that can be prescribed to patients with CES for urinary incontinence?

Answer 32

Oxybutynin hydrochloride

Tolterodine tartrate

Hyoscyamine/hyoscine butylbromide (less effective for urinary continence than oxybutynin or tolterodine but better tolerated

Question 33

What finding of a rectal examination suggests CES?

Answer 33

Loss of anal tone

If you ask patient to squeeze sphincter muscles around your blunt finger, it will be loose