An Overview of Cauda Equina Syndrome

Cauda equina syndrome (CES) is a rare but serious condition that occurs when nerve roots in the lower spinal cord are squeezed or compressed, disrupting motor and sensory function to the bladder and lower extremities. This cluster of nerves roots, called the cauda equina (Latin for "horse's tail"), sends and receives messages to the legs, bladder, and other parts of the body. CES can occur when a ruptured or herniated lumbar disc exerts intense pressure on the cauda equina. If left untreated, CES can lead to serious and irreversible damage, such as chronic incontinence and paralysis of the legs. For this reason, symptoms of CES warrant immediate medical attention and, in many cases, emergency surgery.

Symptoms of cauda equina syndrome can come on acutely, in a matter of hours, or develop gradually over weeks or months.

The symptoms of CES are:

• Severe low back pain
• Sciatica
• Saddle anesthesia, which is numbness or other nerve sensory changes around the anus and the area of your body that sits (in a saddle)
• Pain, numbness, or weakness in one or both legs
• Sexual dysfunction that comes on suddenly
• A loss of reflexes in the extremities
• Loss of bowel control
• Urinary retention (inability to urinate) or overflow urination (incontinence)

The extent of urinary problems can determine how CES is treated. There are two stages cauda equina syndrome based on urinary symptoms:

• CES-Incomplete (CES-I), characterized by symptoms such as altered urinary sensation, loss of desire to void, poor urinary stream, and the need to strain in order to urinate.
• CES-Retention (CES-R), in which bladder control is totally lost

The outcome for people with CES-I at the time of surgery generally is favorable. Those whose CES has deteriorated to CES-R tend to have a poor prognosis.

The most common cause of CES is a ruptured or herniated disc in the lumbar area. Other possible causes may include:

• Trauma or injury to the spine that leads to fractures or dislocations (subluxations)
• Tumors or infections that compress the cauda equina. 
• Spinal stenosis, a narrowing of the spinal column that can be either congenital or acquired
• Bone spurs in the spinal canal
• Tuberculosis or Pott's paralysis
• Iatrogenic side effects—injuries or illness that result from medical or surgical treatment
• Spinal lesions or malignant tumors
• Spinal infection, inflammation, hemorrhage, or fracture
• Complications from a severe lumbar spine injury
• Spinal birth defects

Diagnosing cauda equina syndrome typically requires:

• A medical history of symptoms, general health, and activity level
• A physical exam to assess strength, reflexes, sensation, stability, alignment, and motion​

Testing may include:

• Blood tests for infection
• Magnetic imaging resonance (MRI), which yields three-dimensional images of the spinal cord, nerve roots, and surrounding areas
• Myelography, a type of X-ray or computerized tomography (CT) imaging enhanced by the injection of a contrast material into the cerebrospinal fluid spaces that can show displacement on the spinal cord or spinal nerves
• Specialized nerve testing such as nerve conduction velocity tests and testing electrical activity in muscles (electromyography)

A diagnosis of cauda equina syndrome usually is followed by emergency surgery within 24 to 48 hours. The goal is to relieve compression of the nerves—for example, if a herniated disc is the problem, removing some or all of it (discectomy) may bring relief. Moving swiftly is essential to prevent permanent complications such as nerve damage, incontinence, or leg paralysis. 

Depending on the cause, high doses of corticosteroids also may be prescribed to reduce swelling. If an infection is found to be responsible for CES, antibiotics may be needed. For situations in which a tumor is the cause of CES, surgery to remove it may be necessary, followed by chemotherapy and/or radiation.

Even after surgery, CES can be a challenging condition to deal with. If bladder function has been impaired, recovery of bladder control may take time. It may be necessary to use a catheter or to wear disposable underwear. Frequent urinary infections are also a potential complication.

Loss of bladder or bowel control can be psychologically distressing as well, impacting social life, work, and relationships. Sexual dysfunction can be devastating and may lead to relationship difficulties and depression.

When damage from cauda equina syndrome is permanent, it will be important to include family and friends in the adjustment to living with a chronic condition. Psychological counseling and/or a support group also can be helpful in this transition. Other specialists who can help include:

• Occupational or physical therapist
• Social worker
• Continence advisor or physiotherapist
• Sex therapist

Cauda equina syndrome is a physically and emotionally challenging condition. It affects parts of the body and physical functions that are particularly private. If bladder or bowel incontinence is an issue, physical discomfort can be compounded by emotional distress in the form of embarrassment or and loss of control. The best way to deal with CES is to be proactive: If you're having symptoms that may point to this problem, see a doctor promptly. Delaying treatment can lead to permanent damage.