Cauda Equina Syndrome
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Cauda Equina syndrome is technically not a spinal cord injury, is often referred to as one by the medical community & may result in paraplegia. The spinal cord usually terminates between the first & second lumbar vertebra forming the Conus Medullas. Emerging from this is a bundle of lumbar & sacral nerve roots called the Cauda Equina, which is Latin for horses tail, because of their appearance.
These nerves serve:
- sphincter muscles
- sexual function
- perineal sensation,
- sensation & motor function throughout the legs.
The damaged spinal nerves in the Cauda Equina which result in paralysis are located in the following areas:
- Lumbar nerves: L1-L5
- Sacral nerves: S1-S5
- 1 Coccygeal nerve: Coc1 - responsible for sensation over the coccyx.
Damage to this area is known as Cauda Equina syndrome (CES). CES occurs in approximately 2% of cases of herniated lumbar discs.
Causes of Damage to the Cauda Equina
CES can be caused by a number of different processes, both traumatic & atraumatic.
These may include:
- fracture or dislocation of the lumbar part of the spine
- Epidural Haematoma (a collection of blood that compresses the nerves)
- A penetrating injury such as a gunshot or stab wound
- herniated lumbar discs
- spinal stenosis,
- neoplasms (tumours)
- inflammatory conditions such as Paget's disease & ankylosing spondylitis
- infectious conditions such as spinal or epidural abscesses.
Not all spinal roots may be damaged & symptoms may be asymmetrical or unilateral.
Symptoms of CES may include lower back pain with uni or bilateral weakness and/or sensory abnormality in the legs. Usually asymmetrical weakness with the loss of the reflex dependent on the affected nerve root. Bowel and/or bladder dysfunction with saddle anaesthesia (loss of sensation in the areas where one sits on a saddle) Urinary dysfunction may present as urinary retention or incontinence & bowel dysfunction may include faecal incontinence or constipation. There may be loss of tone & sensation. There may also be sexual dysfunction with impotence, loss of the ability to ejaculate & orgasm.
Diagnosis of CES
It is usually diagnosed by imaging along with history & examination.
The physical exam will include:
- testing the muscle strength of the lower limbs
- evaluating sensation to touch & pain
- checking lower limb reflexes & evaluation anal tone, reflex & sensation.
- X-rays will look for severe arthritis & trauma
- a MRI with & without contrast will provide a detailed look at tumours, infection, inter-vertebral disks, & nerve roots.
Treatment of Damage to the Cauda Equina
Cauda equina syndrome is considered a medical emergency & often prompt surgical decompression of the roots is required to prevent permanent neurological damage.
Medical treatment may be appropriate in certain circumstances depending on the underlying cause of the cauda equina syndrome. Anti-inflammatory drugs such as NSAIDS or corticosteroids can be effective in inflammatory diseases. If caused by infection then antibiotics are administered & people with tumours may receive chemo or radiation therapy
Post operatively lifestyle issues may need addressing such as obesity. Physiotherapy & occupational therapy may be required depending on residual lower limb dysfunction.
Classification of CES
Cauda equina syndrome can be diagnosed into two different classifications:
- Incomplete CES (CESI)
- Complete CES (or CES with true retention; CESR).
Incomplete Cauda Equina Syndrome - CESI
In incomplete cauda equina syndrome (CESI), following examination, patients are diagnosed with motor and sensory changes, including saddle anaesthesia, but have yet to develop full retention or incontinence of either bowel or bladder. The visceral changes they experience are of neurogenic origin, such as straining micturition, possibly using abdominal compression such as the Valsalva or Crede method to assist in urination, loss of urgency, & alteration of urinary sensorium.
Complete Cauda Equina With True Retention - CESR
In cauda equina syndrome with true retention (CESR), true retention has already developed & been diagnosed in patients. In addition to the loss of the visceral neurologic signal to the central nervous system, painless urinary retention, & eventually overflow incontinence is experienced by patients. Likewise, the bowel may experience retention or incontinence. Generally, urinary symptoms are noticed secondary to the usually frequent voiding. This distinction becomes more difficult in the postoperative period in a patient with a Foley catheter. Early diagnosis of cord compression & immediate spinal decompression has been found to halt the progress of neurological deficits.
Prevention of cauda equina syndrome is focused on early diagnosis by identifying the symptoms. While low back pain with leg pain and/or weakness is a common complaint that affects many people, cauda equina syndrome is a rare complication. Recovery depends on early intervention, late diagnosis and treatment lead to more complications and increases the risk of permanent neurological damage, a degree of bladder and/or bowel dysfunction may be permanently lost.
- American Association of Neurological Surgeons: Cauda Equina Syndrome