22. Cauda Equina Syndrome Flashcards

1
Q

A 50-year-old woman presents 4 weeks after receiving an epidural
steroid injection for chronic back pain.

She is now experiencing severe back pain and perineal numbness.

What is the differential diagnosis?

A

Chronic mechanical lower back pain

Lumbar disc pathology

Spinal cord compression from infection, neoplasm or haematoma

Guillain–Barre syndrome

Peripheral nerve disorder

Conus medullaris syndrome

Lumbosacral plexopathy

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2
Q

What are the causes of cauda equina syndrome?

A
  1. Vertebral disc herniation
    Central disc prolapse – incidence of 1%–15%
  2. Neoplasm
    Metastatic prostate cancer, ependymomas, schwannomas
  3. Inflammatory
    Infective e.g. spinal abscess
    Non-infective Diseases which predispose to developing
    vertebral fractures or spinal stenosis, e.g. Paget’s disease
  4. Lumbar spinal stenosis
  5. Trauma
    Violent Injuries to the lower back (gunshots, falls and road traffic accidents)
  6. Post-operative lumbar spine surgery complications
  7. Spinal and epidural anaesthesia resulting in an abscess or haematoma
  8. Epidural steroid injection
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3
Q

What further history would you seek from her?

A

A history of severe low back pain

Weakness of her legs

Pain in one or, more commonly, both legs

Saddle anaesthesia – Does wet toilet paper feel wet?

A recent onset of bladder dysfunction, which may manifest as an inability to
initiate or stop a stream of urine or as overflow incontinence

Recent onset of faecal incontinence

Sensory abnormalities in the bladder or rectum

Recent onset of sexual dysfunction

Severe recent trauma to her back

Recent lumbar spine surgery

A history of cancer

Recent severe infection

Spinal or epidural analgesia

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4
Q

What are the signs of the cauda equina syndrome

A

Saddle anaesthesia.

Residual urine on bladder catheterization indicative of a neurogenic bladder.

Lower motor neuron weakness is found in the plantar flexors and evertors.

Lower limb reflexes are absent or impaired.

Loss of anal tone.

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5
Q

What are the markers of infection?

A

ESR and CRP

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6
Q

What further investigations would you carry out?

A
  1. Haematology
    FBC, INR, APTT
  2. Biochemistry
    Urea, electrolytes and LFT’s

Radiology

Plain X-ray may reveal vertebral fractures, tumour or infection
CT scan
An urgent MRI scan is probably the gold standard investigation
to confirm and localise the lesion.

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7
Q

Anatomy relating to the cauda equina

A

The anatomy of the distal spinal cord and
the cauda equina is responsible for the inconsistency
in presenting signs and symptoms.

The conus medullaris is narrower than the more cephalad
spinal cord and overlies the body of L1.
It represents the termination of the spinal cord in
the proximal lumbar spine.

The conus medullaris continues to taper to form the filum terminale.

The bridle of lumbar and sacral nerves descends
below the conus medullaris to form the cauda equina or horse’s tail.

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8
Q

Roots:

A

The lumbar and sacral nerve roots contain:

Sensory and motor function for the lower limbs

Sensation to the perineum and genitals

Voluntary and involuntary functions:
micturition, defaecation and sexual function.

Compression of the cauda equina may involve
all of the above functions,
sensory only,
motor only, or
only those roots responsible
for bowel and bladder function.

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