Canine syringomyelia: treatment and implications

The term syringomyelia (SM) refers to the development of fluid filled cavities or holes known as a syrinx within the spinal cord of the affected patient (Rusbridge et al, 2007). These syringes are thought to contain extracellular or cerebro spinal fluid (CSF) (Klekamp, 2002). In dogs the most common cause is secondary to chiari malformation (CM). CM characterized by a mis-match in brain and skull size results in obstruction of the foramen magnum and changes in the dynamics of CSF flow. Toy dogs, in particular the Cavalier King Charles Spaniel (CKCS), are most commonly affected by chiari-like malformation and syringomyelia (CMSM) (Lamb and Pfeiffer, 2003; Rusbridge, 2005). Although identified as early as the 1960s (McGrath, 1965), incidence of the disease until the 1990s was thought to be low. However, advancements in diagnostic equipment, such as magnetic resonance imaging (MRI), has lead to an increase in diagnoses in canine patients (Bagley, 2000). With varying presentations, the most significant clinical sign of the condition is pain, thought to be multifactorial resulting from both obstructed CSF flow and spinal cord damage (Rusbridge, 2005). Stalin et al (2008), question stenosis or abnormal widening of the foramen magnum as contributory, while work by Takagi et al (2005), suggest compression of the atlanto-occipital joint as contributory. Cerda-Gonzalez et al (2006), and Meadow et al (2006), identified the condition to be a multifactorial disease with various explanations for its occurrence in the presence of skeletal abnormalities. Human sufferers of the condition report headaches, neck and back pain, and a burning or stretching sensation of the skin (Todor et al, 2000). Some canine patients present with neurological deficits, ataxia and pelvic limb weakness. Other possible clinical signs include scoliosis (Figure 1) and scratching which is typically one sided and without making skin contact (Rusbridge et al, 2000). Affected animals may have an abnormal head carriage position particularily when sleeping.