Syringomyelia is a rare chronic disorder in which a ﬂuid-ﬁlled cavity or cyst forms within the spinal cord. This cyst, which is often called a syrinx, can extend, elongate, and widen over time and cause dysfunction in the spinal cord. Although it may be seen in patients with a Chiari malformation, not everyone with Chiari has a syrinx and not everyone with syringomyelia has Chiari. (Read more about Chiari malformation.)
A syrinx can develop at any time, but it is most commonly diagnosed in young adults. In some individuals, the syrinx does not cause any symptoms and does not progress; in others the syrinx causes neurological symptoms and continues to progress. As a syrinx grows, the nerve ﬁbers inside the spinal cord are compressed and stretched and a wide variety of symptoms can occur, depending upon the size and location of the syrinx. (See Symptoms of Syringomyelia.) As it stretches it may damage the gray matter in the spinal cord and cause pain, loss of sensation, and loss of muscle bulk. Damage to the white matter causes stiﬀness and poor muscle control. Left untreated, a syrinx may eventually lead to paralysis.
What Causes Syringomyelia?
There are many causes of a syrinx such as hydrocephalus, Chiari malformation, trauma, infection, tethered spinal cord or spinal tumors. Sometimes a syrinx will occur without any known cause (referred to as idiopathic syringomyelia). The most common cause of a syrinx is Chiari malformation. There is no known way to prevent syringomyelia.
Reviewed by Jeffrey Greenfield, Ph.D., M.D.
Last reviewed/last updated: April 2021