What Is Syringomyelia?
Syringomyelia is a disease of the spinal cord marked by the formation of a cyst (syrinx). Dogs with a wide syrinx are also more likely to have scoliosis. Over time, the syrinx expands and elongates, destroying the center of the cord. The accumulation of fluid is caused by a cascade of events, starting with obstruction of cerebrospinal fluid flow and spinal cord tethering.
Syringomyelia may result from a congenital defect of the neural tube or trauma to the spinal cord, such as a car accident or serious fall. If a syrinx develops in the cervical region of the spinal cord, it is referred to as communicating syringomyelia.
Some animals with this form of syringomyelia also have hydrocephalus and arachnoiditis, in which the covering of the spinal cord is inflamed. If the cyst or syrinx develops in a segment of the spinal cord damaged by a spinal cord disease, it is sometimes referred to as noncommunicating syringomyelia.
Signs & Symptoms
Clinical signs include progressive weakness in the forelimbs and episodes of involuntary scratching of the flank. The dog’s forelimbs would slide on a slippery surface, and he would be unable to correct this posture. Since the spinal cord connects the brain to the nerves in the extremities, this damage may result in pain, weakness, and stiffness in the back or legs.
The syrinx is diagnosed using an MRI test. With the increasing use of MRI and increased awareness of syringomyelia complex, early detection may enable surgical resolution of this potentially debilitating neurological disease.
Dogs from breeds predisposed to the disease, which are intended for breeding purposes, are often MRI-screened. The earliest change is a central canal dilation. Another early common change is the spinal cord edema or presyrinx state.3
Further studies may also shed light on the heritability of this disease, as it has been reported as a genetic disorder in the King Charles Spaniel. In this breed, syringomyelia occurs as a result of inherited Occipital Hypoplasia/Chiari Type I malformation.