Syringomyelia

Syringomyelia (SM) 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 cord. This accumulation of fluid is caused by a cascade of events starting with obstruction of cerebrospinal fluid (CSF) flow and/or spinal cord tethering.

Causes of Syringomyelia

Syringomyelia may result from a congenital defect of the neural tube and has been reported as a genetic disorder in several breeds of dog, including King Charles Spaniel. In this breed, syringomyelia occurs as a result of inherited occipital hypoplasia/Chiari type I malformation. Trauma to the spinal cord also may result in SM. Spinal cord trauma such as a car accident or serious fall may manifest years later as SM. MRI (Magnetic Resonance Imaging) is the leading diagnostic tool used in determining SM. The MR imager takes pictures of body structures, such as the brain and spinal cord, in vivid detail. MRI Testing will show the syrinx in the spine or any other conditions, such as the presence of a tumor.

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 the disorder also have hydrocephalus (water on the brain), a condition in which CSF accumulates in the skull, or arachnoiditis, in which a 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 of Syringomyelia

Clinical signs include progressive forelimb weakness and episodes of involuntary flank scratching. 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.

Treatment of Syringomyelia

Surgical decompression may be employed in canine patients in the future. With increasing use of MRI and increased awareness of syringomyelia complex, early detection may enable surgical resolution of this potentially debilitating neurological disease. Further studies may also shed light on the heritability of canine CM1, given the apparent predilection in King Charles Spaniels.

References:
1. Small Animal Paediatric Medicine and Surgery. Giselle Hosgood, Johnny D. Hoskins
2. Chiari 1/syringomyelia complex in a King Charles Spaniel. RK Churcher, G Child. In: Aust Vet J, 2000