Cauda Equina Syndrome

A rare but serious low back disorder

Written by Eeric Truumees, MD

Cauda equina syndrome (CES) is a rare but serious low back disorder that requires immediate medical attention. In the lumbar spine (low back) the spinal cord ends and separates into a bundle of nerves. The bundle looks like a horse’s tail and was therefore called the cauda equina (horse’s tail in Latin) by early anatomists.  This bundle of nerves supplies the legs with signals to control the muscles and provide sensation.
Bowel and Bladder Sensations and Function
These nerves are also responsible for normal bowel and bladder sensations and function, including muscles that assist defecation and urination. However, when several of these nerves are compressed or injured at once, bowel and bladder function may be disrupted.  Most commonly, this compression occurs all at once from a disc herniation or fracture and is associated with significant pain.  Occasionally, CES is more difficult to diagnose because its symptoms developed more gradually and vary in intensity.  This can occur in patients with spinal infections, tumors, or spinal stenosis from bone spur formation.

Symptoms Related to Cauda Equina Syndrome
You should see your doctor or seek medical attention quickly if any of the following symptoms develop:

Potential causes
Cauda equina syndrome may be caused by a herniated disc, lumbar tumor, infection in the low back, or lumbar spinal stenosis. Traumatic injury may also cause or contribute to the development of CES; such as falling, car collision, or penetrating injuries (eg, gunshot, stabbing).

Diagnostic process
The doctor performs an in-depth physical and neurological evaluation. This includes reviewing overall health and performing necessary tests. Other parts of the doctor’s exam may include the following:

The yellow arrow in the sagittal T2 weighted MRI (above) shows a large disc herniation at L4-L5;  the cause of Cauda Equina Syndrome in a patient.

Treatment involves relieving the pressure on nerves. Unlike pressure on a single nerve (sciatica or radiculopathy), in which nerve inflammation may be treated with oral steroids or corticosteroid spinal injections, patients with a true cauda equina syndrome typically need urgent surgery to help reduce the risks for long-term problems, such as bowel, bladder, and/or sexual dysfunction, and/or paralysis. At the time of surgery, the disc fragment or other compressing material is directly removed.

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