Prevalence of Chiari-like malformation and Syringomyelia in Cavalier King Charles Spaniels in the Netherlands between 2004 and 2012

Abstract

Chiari-like malformation (CM), or chiari malformation, is most likely the result of a reduced volume of the caudal fossa due to an inappropriately small occipital bone.1 This condition occurs frequently in Cavelier King Charles spaniels (CKCS). The estimated prevalence is approximately 95%. Recent data suggest that CM in CKCS is inherited. One hypothesis is that due to the herniation of the cerebellum (the chiari-like malformation) an abnormal cerebrospinal fluid (CSF) flow exist which in turn might cause in about 50% of the affected dogs a dilatation of the central canal and fluid-containing cavities (syrinx) within the parenchyma of the spinal cord. The latter is a condition known as syringomyelia (SM). Approximately 70% of the CKCS develops SM. It is stated that approximately 10% of dogs with CM and SM exhibit clinical signs. The clinical symptoms consists of episodes of so called phantom scratching towards the neck and face, especially elicited by excitement. As the condition progresses, severe pain attacks and ataxia of the pelvic and thoracic limbs occur.