Syringomyelia in cats

This is a rare disease in cats. In syringomyelia, there is altered CSF flow due to any of an assortment of problems (congenital malformation, tumor, trauma, etc.). The altered flow leads to cavities of fluid forming in the spinal cord. This creates a swelling within the spinal cord and since the cord is confined within a bony protective “cage”, there is no room for the swelling to expand. This creates pain. The driving force for creating the abnormal fluid pocket seems to be the beating of the heart and the pulse it generates. Each pulse generates a pressure wave in the CSF, displacing fluid from the brain and down into the spinal cord. This is how CSF normally accomplishes circulation but in syringomyelia patients there is some kind of obstruction to CSF flow. This creates increased CSF pressure around the obstruction and CSF can actually be pumped directly into the spinal cord tissue. This distends the cord, creating fluid pockets. The fluid is not CSF but simply what is called “extracellular fluid.” The distended cord exacerbates the obstruction of CSF flow thus creating a progressive problem (i.e. a viscious cycle).

One case has been described by Tani et al in 2001. A 3-month-old male Japanese cat with feline parvovirus infection, showing central and cervical nerve abnormalities, was diagnosed as hydrocephalus and syringomyelia by use of magnetic resonance imaging (MRI). The cat was maintained clinically by medical treatment even though he could not stand. The MRI scans obtained about 5 months later showed that the ventricles had increased in size and the cervical syrinx had extended into the thoracic spinal cord. Ventriculoperitoneal (VP) shunt was performed. One week after surgery, neurological conditions had improved. At the postoperative MR images, the ventricles had decreased in size and the syrinx in the cervical and thoracic spinal cord could no longer be seen. The cat was still alive and was able to walk well.