Cauda equina syndrome

Cauda equina syndrome
Classification and external resources
Cauda equina and filum terminale seen from behind.
ICD-10	G83.4
ICD-9	344.6
DiseasesDB	31115
eMedicine	emerg/85 orthoped/39
MeSH	C10.668.829.800.750.700

Cauda equina syndrome (CES) is a serious neurologic condition in which there is acute loss of function of the lumbar plexus, neurologic elements (nerve roots) of the spinal canal below the termination (Conus medullaris) of the spinal cord.

Causes

After the conus medullaris, the canal contains a mass of nerves (the cauda equina or "horse-tail") that branches off the lower end of the spinal cord and contains the nerve roots from L1-5 and S1-5. The nerve roots from L4-S4 join in the sacral plexus which affects the sciatic nerve, which travels caudally (toward the feet).

Tumors and lesions

Any lesion which compresses or disturbs the function of the cauda equina may disable the nerves although the most common is a central disc prolapse. Metastatic disease may also be a cause.

Trauma

Direct trauma from lumbar puncture can also cause cauda equina syndrome. Other trauma-related causes include burst fractures resulting in posterior migration of fragments of the vertebral body, severe disc herniations, spinal anaesthesia involving trauma from catheters and high local anaesthetic concentrations around the cauda equina. Penetrating trauma such as knife wounds or ballistic trauma.

Spinal stenosis

CES can be caused by lumbar spinal stenosis, which is when the diameter of the spinal canal narrows. This could be the result of a degenerative process of the spine (such as osteoarthritis) or a developmental defect which is present at birth. In the most severe cases of spondylolisthesis cauda equina syndrome can result.

Inflammatory conditions

Chronic spinal inflammatory conditions such as Paget disease, chronic inflammatory demyelinating polyneuropathy and ankylosing spondylitis can cause it. This is due to the spinal canal narrowing that these kind of syndromes can produce.

Signs

Signs include weakness of the muscles of the lower extremeties innervated by the compressed roots (often paraplegia), sphincter weaknesses causing urinary retention and post-void residual incontinence as assessed by catheterizing after the patient has urinated. Also, there may be decreased anal tone and consequent fecal incontinence; sexual dysfunction; saddle anesthesia; bilateral leg pain and weakness; and bilateral absence of ankle reflexes. Pain may, however, be wholly absent; the patient may complain only of lack of bladder control and of saddle-anaesthesia, and may walk into the consulting-room.

Diagnosis is usually confirmed by an MRI scan or CT scan, depending on availability. If cauda equina syndrome exists, surgery is an option depending on the etiology discovered and the patient's candidacy for major spine surgery.

Treatment/management

The management of true cauda equina syndrome frequently involves surgical decompression.When cauda equina is caused by a herniated disk early surgical decompression is recommended.

Cauda equina syndrome of sudden onset is regarded as a medical/surgical emergency. Surgical decompression by fish tail means of laminectomy or other approaches may be undertaken within 48 hours of symptoms developing if a compressive lesion, e.g. ruptured disc, epidural abscess, tumour or haematoma is demonstrated. This treatment may significantly improve the chance that long-term neurological damage will be avoided.

If cauda equina is caused by a trauma then the patient should be immobilized.

Surgery may be required to remove blood, bone fragments, a tumour or tumours, a herniated disc or an abnormal bone growth.If the tumour cannot be removed surgically and it is malignant then radiotherapy may be used as an alternative to relieve pressure, with spinal neoplasms chemotherapy can also be used. If the syndrome is due to an inflammatory condition e.g. ankylosing spondylitis, anti-inflammatory , including steroids can be used as an effective treatment. If a bacterial infection is the cause then an appropriate course of antibiotics can be used to treat it.

Cauda equina can occur during pregnancy due to lumbar disc herniation; age of mother increases the risk. Surgery can still be performed and the pregnancy does not adversely affect treatment. Treatment for those with cauda equina can and should be carried out at any time during pregnancy.

Lifestyle issues may need to be addressed post - treatment. Issues could include the patients need for physiotherapy and occupational therapy due to lower limb dysfunction. Obesity might also need to be tackled.

Prognosis

The prognosis for complete recovery is dependent upon many factors. The most important of these is the severity and duration of compression upon the damaged nerve(s). Generally, the longer the time before intervention to remove the compression causing nerve damage, the greater the damage caused to the nerve(s).

Damage can be so severe that nerve regrowth is impossible, and the nerve damage will be permanent. In cases where the nerve has been damaged but is still capable of regrowth, recovery time is widely variable. Surgical intervention with decompression of the cauda equina can assist recovery. Delayed or severe nerve damage can mean up to several years' recovery time because nerve growth is exceptionally slow.

Review of the literature indicates that around 50-70% of patients have urinary retention (CES-R) on presentation with 30-50% having an incomplete syndrome (CES-I). The latter group, especially if the history is less than a few days, usually requires emergency MRI to confirm the diagnosis followed by prompt decompression. CES-I with its more favourable prognosis may become CES-R at a later stage.

Prevention

Early diagnosis can allow for preventive treatment. Signs that allow early diagnosis include changes in bowel and bladder function and loss of feeling in groin.

External links

• 06-093c. at Merck Manual of Diagnosis and Therapy Home Edition
• Duke Orthopedics cauda_equina_syndrome