Syringomyelia (sear-IN-go-my-EEL-ya) is a disorder in which a cyst forms within the spinal cord. This cyst, called a syrinx, expands and elongates over time, destroying the center of the spinal cord. Since the spinal cord connects the brain to nerves in the extremities, this damage results in pain, weakness, and stiffness in the back, shoulders, arms, or legs. Other symptoms may include headaches and a loss of the ability to feel extremes of hot or cold, especially in the hands. Each patient experiences a different combination of symptoms. Magnetic resonance imaging (MRI) has significantly increased the number of syringomyelia cases diagnosed in the beginning stages of the disorder. Signs of the disorder tend to develop slowly, although sudden onset may occur with coughing or straining. If not treated surgically, syringomyelia often leads to progressive weakness in the arms and legs, loss of hand sensation, and chronic, severe pain. In most cases, the disorder is related to a congenital abnormality of the brain called a Chiari I malformation. This malformation occurs during the development of the fetus and causes the lower part of the cerebellum to protrude from its normal location in the back of the head into the cervical or neck portion of the spinal canal. Syringomyelia may occur as a complication of trauma, meningitis, hemorrhage, a tumor, or arachnoiditis. Symptoms may appear months or even years after the initial injury, starting with pain, weakness, and sensory impairment originating at the site of trauma. Some cases of syringomyelia are familial, although this is rare.
A watery, protective substance known as cerebrospinal fluid (CSF) normally flows around the spinal cord and brain, transporting nutrients and waste products. It also serves to cushion the brain. In early development, CSF also fills a small canal through the center of the spinal cord—the central canal—which then collapses normally over time.
A number of medical conditions can cause an obstruction in the normal flow of CSF, redirecting it into the central canal, and ultimately into the spinal cord itself. For reasons that are only now becoming clear, this redirected CSF fills the expanding central canal and results in syrinx formation. Pressure differences along the spine cause the fluid to move within the cyst. Physicians believe that it is this continual movement of fluid that builds pressure around and inside the spinal cord, and results in cyst growth and further damage to the spinal cord tissue.
Generally, there are two forms of syringomyelia. In most cases, the disorder is related to an abnormality of the brain called a Chiari I malformation, named after the physician who first characterized it. This anatomic abnormality causes the lower part of the cerebellum to protrude from its normal location in the back of the head into the cervical or neck portion of the spinal canal. A syrinx may then develop in the cervical region of the spinal cord. Because of the relationship that was once thought to exist between the brain and spinal cord in this type of syringomyelia, physicians sometimes refer to it as communicating syringomyelia. Symptoms usually begin between the ages of 25 and 40 and may worsen with straining or any activity that causes CSF pressure to fluctuate suddenly. Some patients, however, may have long periods of stability. Some patients with this form of the disorder also have hydrocephalus, in which CSF accumulates in the skull, or a condition called arachnoiditis, in which a covering of the spinal cord--the arachnoid membrane--is inflamed.
The second major form of syringomyelia occurs as a complication of trauma, meningitis, hemorrhage, a tumor, or arachnoiditis. Here, the syrinx or cyst develops in a segment of the spinal cord damaged by one of these conditions. The syrinx then starts to expand. This is sometimes referred to as noncommunicating syringomyelia. Symptoms may appear months or even years after the initial injury, starting with pain, weakness, and sensory impairment originating at the site of trauma.
The primary symptom of post-traumatic syringomyelia is pain, which may spread upward from the site of injury. Symptoms, such as pain, numbness, weakness, and disruption in temperature sensation, may occur on one or both sides of the body. Syringomyelia can also adversely affect sweating, sexual function, and, later, bladder and bowel control.
In addition, one form of the disorder involves a part of the brain called the brainstem. The brainstem controls many of our vital functions, such as respiration and heartbeat. When syrinxes affect the brainstem, the condition is called syringobulbia. Some cases of syringomyelia are familial, although this is rare.
Surgery is usually recommended for syringomyelia patients. Recurrence of syringomyelia after surgery may make additional operations necessary; these may not be completely successful over the long term.
In some patients it may be necessary to drain the syrinx, which can be accomplished using a catheter, drainage tubes, and valves.
In the absence of symptoms, syringomyelia is usually not treated. In addition, a physician may recommend not treating the condition in patients of advanced age or in cases where there is no progression of symptoms. Whether treated or not, many patients will be told to avoid activities that involve straining.
Symptoms usually begin between the ages of 25 and 40 and may worsen with straining or any activity that causes cerebrospinal fluid pressure to fluctuate. Some patients, however, may have long periods of stability. Surgery results in stabilization or modest improvement in symptoms for most patients. Delay in treatment may result in irreversible spinal cord injury.
Investigators have found that as the heart beats, syrinx fluid is forced downward. This finding suggests a role for the cardiovascular system in syringomyelia.
Surgical techniques are also being refined by the neurosurgical research community. It is also important to understand the role of birth defects in the development of hindbrain malformations that can lead to syringomyelia. Dietary supplements of folic acid during pregnancy have already been found to reduce the number of cases of certain birth defects.
Diagnostic technology is another area for continued research. contrast dyes. Patients can expect even better techniques to become available in the future from the research efforts of scientists today.
|American Chronic Pain Association (ACPA)
P.O. Box 850
Rocklin, CA 95677-0850
Tel: 916-632-0922 800-533-3231
|Christopher and Dana Reeve Foundation
636 Morris Turnpike
Short Hills, NJ 07078
Tel: 973-379-2690 800-225-0292
|March of Dimes Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: 914-428-7100 888-MODIMES (663-4637)
|National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
|National Spinal Cord Injury Association
1 Church Street
Rockville, MD 20850
|Paralyzed Veterans of America (PVA)
801 18th Street, NW
Washington, DC 20006-3517
Tel: 202-USA-1300 (872-1300) 800-424-8200
|Spina Bifida Association of America
4590 MacArthur Blvd. NW
Washington, DC 20007-4266
Tel: 202-944-3285 800-621-3141
|Spinal Cord Society
19051 County Highway 1
Fergus Falls, MN 56537
Tel: 218-739-5252 or 218-739-5261