Neurology is not my favourite area of medicine and when listening to mind-blowingly clever people discussing this topic I’m always worried it will go completely over my head, or even worse my mind may start to wander. This was most definitely not the case with last week’s webinar covering ‘Chiari’ Type Malformation and Syringomyelia (CMSM) led by Dr Clare Rusbridge. The entire webinar was fascinating from start to finish and I could not tear my eyes away from the screen, proving that even ‘neurophobes’ like myself will be deeply engaged by this webinar.

Initially Clare dispelled the view that CMSM is just a disease of Cavalier King Charles Spaniels and explained that it’s a condition which can affect any brachycephalic toy breed. For this reason Clare advises the next time you see a weak Yorkshire Terrier or painful Chihuahua, CMSM should be considered as a differential.

Chiari malformation is a trait of the brachycepahlic breed as there is rostral caudal shortening of the skull which essentially squashes the cerebellum and medulla pushing them partly through into the foramen magnum. This disrupts the flow of cerebrospinal fluid and it is this obstruction which causes syringomyelia (fluid cavities within the spinal cord). Clare explained there is a theory that humans are genetically programmed to like things that look like babies. So the question has to be asked whether we are progressively selecting for this Chiari malformation in dogs in an attempt to replicate the look of a baby?

Clare also asked the participating audience what they considered to be the main clinical sign associated with CMSM. The majority went for the correct answer, pain, NOT paralysis or seizures. Clare advised paralysis was not likely to be encountered in CMSM as it has been found that an animal only needs 5% of its spinal cord to function in order to walk, a problem not associated with CMSM. Seizures, although common, in the CKCS are again very unlikely to be associated with CMSM and are most likely to be associated with idiopathic epilepsy.

So how do dogs with CMSM show they are in pain? Clare explained these animals are very unlikely to demonstrate obvious signs of pain such as howling. CM is most likely to cause headaches – and what do we do when we have a headache? We go and lie down somewhere quiet, and this is exactly what affected dogs do. Affected dogs may also sleep in an unusual way which helps alleviates the pain. Clare used an example of a dog which would always elevate its head onto the cool surface whilst sleeping. Animals may also scratch at their ears excessively despite there being no signs of external ear disease and can also demonstrate postural pain such as pain on being lifted.

Pain associated with syringomyelia includes the infamous ‘shoulder scratching’ which has a very rhythmic action and is known by breeders as ‘air guitar’ or ‘phantom scratching’. This is thought to be a hyperactive reflex in response to touch which can be triggered by collars when dogs are on a walk or even just excitement. Scoliosis and torticollis can also be present and should not be confused with vestibular syndrome.

As these dogs suffer pain clearly their quality of life will be affected and Clare advises that treatment is essential. However she has heard of circumstances where vets have stated a hopeless prognosis which is not the case. These dogs can continue with a good quality of life if the correct treatment is used with surgery and medical therapy both being options. These were discussed in depth by Clare. Medical treatment usually involves polypharmacy utilising NSAIDS for non-neuropathic pain, gabapentin for neuropathic pain and CSF reducing drugs such as cimetidine and omeprazole. Surgery involves a cranial cervical decompression which enlarges the foramen magnum. However Clare advises although this method does successfully reduce pain, the syringomyelia persists and in her experience about 50% deteriorate within 2.5 years.

The length of this blog gives you some idea of the amount of relevant and useful information available within this veterinary webinar and I highly recommend taking an hour of your time to log into ‘The Webinar Vet’ and learn more about CMSM, I promise you will not regret it!