Cauda Equina Syndrome

Question 1

Define Cauda Equina syndrome and its types

Answer 1

a constellation of symptoms due to compression of the Cauda Equina

CES-S (suspected): bilateral sciatica, subjective sphincter issues / perianal sensory disturbance
CES-I (incomplete) voluntary control of micturition, objective signs/evidence of CES
CES-R (retention/complete) complete urinary retention, overflow incontinence

Question 2

Describe the anatomy of cauda equina

Answer 2

Conus medullaris (termination of the spinal cord at L1/L2)
Filum terminale (extension of pia mater from conus to sacrum)

Cauda equina (L2 and below, and filum terminale forming the “horse’s tail”)
- Lower limb sensation/power
- S2-4 (bladder control, EAS, external genitalia, perianal sensation)

Question 3

What are the causes of cauda equina

Answer 3

V
I abscess
T trauma, haematoma
A
M
I iatrogenic spinal surgery
N tumour
C congenital spinal abnormalities
D spinal cord disc prolapse (L4/5, L5/S1)
E

Question 4

Symptoms and signs of cauda equina

Answer 4

Red flags: Act now
Bilateral sciatica (50%): back pain
Saddle anaesthesia
Lower limb weakness

White flags: too late
Urinary retention
Urinary/faecal incontinence
- Urinary retention (bladder distension as sensation of fullness lost)
- Urinary incontinence (by loss of sensation when passing urine)
- Faecal incontinence (due to loss of sensation of rectal fullness)

Other
Reduced sexual function

Signs
Lower limb neurological examination
Saddle anaesthesia
DRE (anal tone/sensation)

Question 5

Investigations for cauda equina

Answer 5

Bladder scan (urinary retention)
MRI / CT myelogram (2nd line)

Question 6

Management for cauda equina syndrome

Answer 6

PO dexamethasone (if metastatic; whilst awaiting MRI results)
Decompressive laminectomy (≤48 hours from bladder dysfunction)