A Guide to Cauda Equina Syndrome

Medically Reviewed By Seunggu Han, M.D.
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Cauda equina syndrome is a rare condition that affects the nerve roots at the bottom of the spinal cord. It is vital to recognize early symptoms of cauda equina syndrome. You may lose control of urination — finding it difficult to start or stop peeing. Without prompt treatment, permanent paralysis and bowel or bladder problems can occur.

This article explains cauda equina syndrome symptoms, causes, diagnosis, and treatment.

What is cauda equina syndrome?

illustration of cauda equina, spinal cord, vertebrae, sacrum, and sciatic nerves
Illustration by Jason Hoffman

The cauda equina is a group of nerve roots and nerves that extend off the end of the spinal cord. In Latin, cauda means tail and equina means horse. It gets this name because it resembles a horse’s tail.

The cauda equina provides sensory and motor innervation to the lower limbs and pelvic area, which helps you move your legs and feet. It also allows you to control your bladder and bowel and feel sexual sensation.

In cauda equina syndrome, these nerves become compressed. For most people, a herniated disc is the cause. The compression can cause permanent damage, with the nerves that control the bladder and bowel being highly at risk. 

Because irreversible changes are possible, cauda equina is an emergency. It requires surgery to decompress the nerves.

What are the symptoms of cauda equina syndrome?

The symptoms of cauda equina syndrome can vary in severity depending on the amount of compression. They can also vary in character depending on the specific area of compression.

The most common symptoms are urinary retention and bladder incontinence. Retention means you do not feel the sensation or urge to urinate, even though your bladder is full. Incontinence means you cannot control the flow of urine; you may pee without control, even when you try to stop it.

Other cauda equina red flags include:

  • bowel incontinence
  • saddle anesthesia, or loss of sensation in the anus, perineum, genitals, and buttocks
  • sciatica, which is low back pain that runs down the back of the legs
  • sexual dysfunction, including impotence
  • weakness, paralysis, or reduced sensation in the lower limbs

Typically, people experience loss of sensation in the perineal area with bladder dysfunction. In people assigned male at birth, the perineum is the area between the anus and base of the penis. In people assigned female at birth, the perineum is the area between the anus and opening of the vulva.

You should contact a medical professional immediately if you have any symptoms of cauda equina syndrome.

What causes cauda equina syndrome?

Cauda equina syndrome is due to compression on the nerves at the end of the spinal cord. The most common cause is a herniated disc.  

Other possible causes include spinal:

  • arteriovenous malformations
  • anomalies present at birth
  • hemorrhage (bleeding)
  • infections
  • inflammation
  • injuries, strains, and trauma
  • anesthesia or surgery
  • tumors
  • vertebral fractures

How is cauda equina syndrome diagnosed?

It can be difficult to diagnose cauda equina syndrome because the symptoms are generally not specific — other conditions can have similar symptoms. This makes testing very important, in order to diagnose it early.

To start, doctors will take a careful medical history and perform an exam.

An MRI is the gold standard for diagnosing cauda equina syndrome. Ideally, the MRI should take place as soon as possible. A CT myelogram is an alternative test for those who cannot have an MRI. However, this test requires contrast injection into the spinal canal.

Doctors may also order a bladder scan to check for urinary retention.

How is cauda equina syndrome treated?

Treatment for cauda equina syndrome is emergency surgery to decompress the nerves. Ideally, the surgery should take place within 48 hours of the onset. This offers the best chance of the nerves recovering and avoiding permanent loss of movement or sensation. 

What are the potential complications?

Complications are common with cauda equina syndrome, even after surgery. They can include:

  • bowel incontinence
  • saddle anesthesia
  • sciatica
  • sexual dysfunction
  • urinary retention requiring self-catheterization

These problems can persist for several weeks to years. Rehabilitation medicine and physical therapy can help improve function and sensation. Doctors may recommend prescription medications to treat nerve-related pain that continues.

Lingering effects from cauda equina syndrome are a cause of disability. They can also adversely affect quality of life and take a toll on social, personal, and work relationships. Counseling with a mental health professional can provide emotional support to deal with these issues.

What is the outlook?

The outlook for cauda equina syndrome depends on how quickly surgery takes place after its onset. Earlier treatment has a better prognosis than when there are delays. The longer the compression lasts, the more likely that the functional and structural changes will be permanent. In general, surgery within 48 hours of onset has the best prognosis. 

Frequently asked questions

Seunggu Han, MD reviewed the following questions.

What are the first signs of cauda equina syndrome?

The typical first signs of cauda equina syndrome are loss of sensation in the perineum, along with bladder dysfunction.

What are the red flags for cauda equina syndrome?

Red flags for cauda equina syndrome include:

  • urinary and fecal incontinence
  • urinary retention
  • saddle anesthesia, or loss of sensation in the anus, perineum, genitals, and buttocks
  • sciatica
  • sexual dysfunction, including impotence
  • weakness, paralysis, or reduced sensation in the lower limbs

Can you walk with cauda equina syndrome?

Problems with movement in the lower limbs can occur with cauda equina syndrome. The problem can range from weakness to paralysis.

Summary

Cauda equina syndrome is a rare condition that affects the nerves and nerve roots at the end of the spinal cord. Theses nerves supply the lower limbs and pelvic area. They provide both sensory and motor functions for these body areas. Compression, usually from a herniated disc, disrupts these nerves. 

Cauda equina syndrome is a surgical emergency. Prompt treatment can prevent permanent nerve damage. However, many people have lingering effects for weeks to years.

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Medical Reviewer: Seunggu Han, M.D.
Last Review Date: 2022 Sep 14
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