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Cauda Equina Syndrome

By

Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Last full review/revision Feb 2020| Content last modified Feb 2020
Click here for the Professional Version
Topic Resources

Cauda equina syndrome occurs when the bundle of nerves that extends from the bottom of the spinal cord is compressed or damaged.

  • The most common cause of cauda equina syndrome is a herniated disk.

  • Cauda equina syndrome causes severe pain in the lower back, urinary problems (such as incontinence). and loss of sensation in the buttocks, genital area, bladder, and rectum.

  • Doctors immediately evaluate people with symptoms of cauda equina syndrome and do magnetic resonance imaging or computed tomography to confirm the diagnosis.

  • Surgery is often needed to relieve pressure on the cauda equina, and pain relievers and corticosteroids are used to relieve pain.

A bundle of nerves extends downward from the bottom of the spinal cord, through the lower back bones (vertebrae) and over the bone at the base of the spine (sacrum). This bundle is called the cauda equina, which means horse’s tail in Latin, because that is what the bundle looks like. The symptoms that result from compression of or damage to the cauda equina are called the cauda equina syndrome.

Cauda Equina Syndrome

A bundle of nerves extends downward from the bottom of the spinal cord, through the lower back bones (vertebrae) and over the bone at the base of the spine (sacrum). This bundle is called the cauda equina, which means horse’s tail in Latin, because that is what the bundle looks like.

The cauda equina may be compressed by a ruptured or herniated disk, a tumor, or an abscess. It may be damaged by an injury or swell because it becomes inflamed (as occurs in ankylosing spondylitis). The symptoms that result are called the cauda equina syndrome.

Cauda Equina Syndrome

Causes

The most common cause of cauda equina syndrome is

  • A ruptured or herniated disk in the lower spine, especially in people who are born with a narrow spinal canal

Other causes include the following:

  • Infection of the spinal cord

  • An abscess (a collection of pus) pressing on the cauda equina

  • Spinal stenosis (narrowing of the passageway that contains the spinal cord)

  • Arteriovenous malformation (an abnormal connection between blood vessels supplying the cord)

  • Complications after surgery on the spine

Some of these conditions cause inflammation and/or swelling, putting pressure on the nerves.

Symptoms

People with cauda equina syndrome may have severe pain in the lower back, usually due to the disorder causing cauda equina syndrome. People may lose sensation in the buttocks, genital area, bladder, and rectum—the area of the body that would touch a saddle (called saddle anesthesia). That is, these people may be less able to feel pain, touch, temperature, and vibration in these areas.

Sensation and muscle control may be impaired in the lower legs.

Other symptoms of cauda equina syndrome may include the following:

Without treatment, cauda equina syndrome can cause complete paralysis.

Diagnosis

  • A doctor's evaluation

  • Imaging tests

Doctors suspect cauda equina syndrome based on symptoms and results of a physical examination. However, symptoms tend to vary.

Magnetic resonance imaging (MRI) or computed tomography (CT) can usually confirm the diagnosis. Sometimes another imaging test, such as myelography with CT, is done to rule out other disorders that cause similar symptoms.

Treatment

  • Surgery

  • Usually corticosteroids

People who have cauda equina syndrome require immediate medical attention.

Doctors focus on treating the disorder causing cauda equina syndrome. For example, surgery is done immediately to relieve pressure on the cauda equina caused by a herniated disk. Such treatment can prevent permanent damage.

Nonsteroidal anti-inflammatory drugs (NSAIDs) or other pain relievers are used. If these drugs do not relieve the pain, corticosteroids, given by mouth or injection, may help. Corticosteroids can also reduce swelling.

How well a person recovers often depends on the cause and how promptly it are treated. Symptoms are more likely to lessen or go away if the cause is identified and is treated immediately.

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