Cauda Equina Syndrome

Introduction

The human nervous system is composed of two main parts, namely, the central and peripheral nervous systems. The former includes the brain and spinal cord which act as the main centers for gathering and processing information. The spinal cord communicates with all other parts of the body through the medium of nerves that emerge from it. The points where these main nerves emerge from the spinal cord are known as spinal nerve roots. These spinal nerves then branch out into a network of nerves that reaches every part of the body. This is known as the peripheral nervous system. Hence, the nerve roots serve a very important purpose because they facilitate communication between the central and peripheral nervous systems.

Different groups of spinal nerves are responsible for sensory and motor function in different areas of the body. For instance, a group of about 10 pairs of nerves emerging from the lumbar area of the spine (the lower back) is responsible for innervation of the pelvic region and the lower limbs or the legs. Hence, these nerves are also responsible for sexual function and bladder and bowel control. Because they form a dense clump as they emerge from the base of the spine, this group of nerves and nerve roots is referred to by the name ‘cauda equina’ which translates to ‘horse tail’.

What Is Cauda Equina Syndrome?

Cauda equina syndrome is a rare but life-threatening condition in which pressure is exerted on the group of nerves and nerve roots known collectively as the cauda equina. This leads to loss of control of the pelvic organs and the legs. Unless the forces of compression are relieved immediately, the patient risks permanent loss of sensory and motor control in the areas governed by the cauda equina. This means loss of bladder and bowel control as well as movement and sensation in the legs. Patients will also lose sexual function and sensation in the pelvic area.

This condition is to be treated as a medical emergency. For the reasons stated above, patients suffering from cauda equina syndrome should receive prompt medical attention.

What Causes It?

There can be a few different factors responsible for the abnormal pressure being exerted upon these nerves and nerve roots. For instance, the patient may have a tumor that presses into the spinal cord. Alternatively, he or she may be suffering from a condition known as spinal stenosis, particularly lumbar spinal stenosis. This involves progressive narrowing of the narrow space within the vertebral column through which the spinal cord passes.

Normally, peripheral nerves are protected from mechanical shocks and injury by an outer sheath of connective tissue known as the epineurium. In the case of the cauda equina nerve roots, their epineurium sheath is not as well developed. Hence, they are considered especially susceptible to injury.

A fuller list of potential causes appears below:

• Injury. This also includes trauma sustained during surgery.
• Inflammation.
• Infection.
• Abscess.
• Blood clots in the spinal veins. This is known as deep vein thrombosis.
• The pressure exerted by a tumor. This may be a benign tumor or a malignant one (whether primary or metastatic).
• Herniated disc.
• Ruptured disc.
• Vascular Malformations.
• Multiple sclerosis.
• Ankylosing spondylitis.
• Paget disease.
• Lumbar spinal stenosis.
• Bleeding or hemorrhage in the spinal cord.
• A fracture in the vertebral column.
• Spina bifida, a congenital spinal defect.
• Tethered cord syndrome.

What Are The Symptoms Of Cauda Equina Syndrome?

In some patients, the condition sets in suddenly. In other cases, the onset of symptoms is more gradual. The extent of sensory and motor disturbance depends on the degree of compression placed on the cauda equina and the nature of the disturbance. As a result of nerve compression, patients typically experience neuromuscular difficulties involving some amount of motor and sensory deficits in the legs and the saddle area. The saddle area includes the groin, buttocks and the genital region. The internal pelvic organs are affected which leads to problems in the urogenital tracts.

A more detailed list of symptoms appears below. Not every patient will necessarily experience all of the symptoms listed below. However, they are like to have at least a few of them in varying degrees of severity.

• Weakness in the affected area, usually the legs.
• Numbness.
• Abnormal sensations such as tingling.
• Pain. The quality and intensity of pain vary.
• Inability to stand or walk normally.
• Stiffness in the back.
• Urinary incontinence.
• Urine retention.
• Fecal incontinence.
• Loss of sexual function.

What Are Some Possible Complications?

Cauda equina syndrome is considered a medical emergency. Unless immediate steps are taken to relieve the force pinching the nerves and nerve roots of the cauda equina, the patient may be left with permanent deficits and disabilities. The patient may permanently lose physical control of the affected areas. This means loss of bowel and bladder control, rendering the patient incontinent. The legs may become paralyzed and there may be a loss of sexual function as well.

How Is It Diagnosed?

Successful diagnosis of cauda equina syndrome relies on radiological testing. In view of the neurological nature of symptoms being displayed by the patient, the medical team may already be alerted to the possibility of some form of damage involving the lower section of the spine. The important part is to find out what exactly is responsible for this condition, whether that might be a tumor or some other factor related to infection or existing disorder of the spine. The best way to do this is by means of magnetic resonance imaging (MRI).

Treatment

The sooner that the problem is identified, the better the overall outlook for the patient’s survival with minimal lasting damage to the nerves. Most often, surgery is necessary for immediate decompression. Surgery undertaken within a window of about 24 hours following the onset of symptoms is considered to have the best prognosis for recovery of neurological function. Even so, the patient may need intensive rehabilitative therapy and support before full function can be restored. Some amount of leg pain or lower back pain may persist even after surgery and the amount it takes for full recovery depends on the extent of damage sustained and other factors such as the general health of the patient. Those with urinary or bowel incontinence can manage the condition to an appreciable extent with the use of adult diapers. Patients will generally need some amount of physical therapy. Some are even advised to avail of the services of sex therapists in order to restore normal sexual function.

Prevention

There are no specific ways to prevent the onset of cauda equina syndrome. The best way to tackle this condition is to get an as early diagnosis as possible and starting the treatment immediately to avoid further complications. Early diagnosis is also important because the symptoms, back, and leg pains are quite common complaints and thus it becomes difficult to correctly identify this condition.

Cauda equina syndrome is a form of neuropathy. A neuropathy is any condition that affects nerves or impairs their normal function. In this case, the damage is caused when the nerves of the cauda equina suffer compression or pinching as a result of injury, infection or even surgical complications. The damage caused may be irreversible. In order to prevent this, a patient showing signs consistent with cauda equina symptom should be treated as expediently as possible. Most often, this requires surgical intervention in order to relieve the pressure on the nerves and nerve roots forming the cauda equina.

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