Syringomyelia

Image:Collapsed Syringomyelia.JPGSyringomyelia (sear-IN-go-my-EEL-ya) is a disorder in which a cyst or tubular cavity 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. more...

Each patient experiences a different combination of symptoms.

Other, more common disorders share the early symptoms of syringomyelia. In the past, this has made diagnosis difficult. The advent of one outpatient test, however, called magnetic resonance imaging or MRI, has significantly increased the number of syringomyelia cases diagnosed in the beginning stages of the disorder.

About 21,000 American men and women have syringomyelia, with symptoms usually beginning in young adulthood. Signs of the disorder tend to develop slowly, although sudden onset may occur with coughing, straining, or myelopathy. If not treated surgically, syringomyelia often leads to progressive weakness in the arms and legs, loss of hand sensation, and chronic, severe pain.

The Cause

A watery, protective substance known as cerebrospinal fluid normally flows around the spinal cord and brain, transporting nutrients and waste products. It also serves to cushion the brain.

A number of medical conditions can cause an obstruction in the normal flow of cerebrospinal fluid, redirecting it into the spinal cord itself. For reasons that are only now becoming clear, this results in syrinx formation. Cerebrospinal fluid fills the syrinx. Pressure differences along the spine cause the fluid to move within the cyst. Physicians believe that it is this continual movement of fluid that results in cyst growth and further damage to the spinal cord.

Different Origins

Generally, there are two forms of syringomyelia.

The first major form consists of most cases, whereby the disorder is related to an abnormality of the brain called an Arnold-Chiari 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. Here, 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 suddenly. Some patients, however, may have long periods of stability. Some patients with this form of the disorder also have hydrocephalus, in which cerebrospinal fluid 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.

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