by  John V. Ioia, MD, PhD

Neurology: Reprinted from AKC Gazette June 2021

 I found that Epilepsy and the CKCS was an interesting but difficult topic to write about for several reasons.  The first, like an onion, the more I researched, the more layers of information I uncovered and some information out there is old and perhaps incorrect.  Like some other diseases affecting the CKCS there is a perpetuating of assumed facts.

Seizures do occur in dogs and there are different types.  Seizures may be brief and even go unnoticed, where the dog may simply appear to be gazing into space for a few moments.  This is termed an “Absence seizure.”  A more common generalized seizure, similar to a human grand mal seizure is a generalized motor event with the dog laying on its side, moving or paddling its limbs, whining, crying or barking and unaware of its surroundings.  It may urinate of defecate and when it’s over the will be a post-seizure recovery period, lasting as long as 30 minutes or more where the dog will remain unaware of what’s going on.

Epilepsy is the most common neurological disorder seen in dogs, and has been estimated to affect approximately 0.75% of the general canine population.

Diagnosing Epilepsy in dogs can be difficult.  First, one must rule out other causes of seizure-like behavior like cardiac events or vestibular disease, hyperlipidemia and liver disease.

Canine Epilepsy is classified into three categories.  Structural Epilepsy, is diagnosed where “Observable damage” or brain malformation can explain the reason for the seizure.  An intracranial tumor, head trauma, congenital malformation, post-stroke and post-inflammatory diseases such as meningitis may be the cause and can be diagnosed by X-ray, MRI, cerebrospinal fluid analysis and serum labs.

Epilepsy of Unknown Cause is the term used to describe Epilepsy where a structural cause is suspected but not identified.

The majority of Canine Epilepsy is termed Idiopathic, where there is no identifiable structural, metabolic or toxic cause, has a repetitive pattern and is assumed to be genetic in origin.  The age of presentation in CKCS and all dogs is the same, 6 mos. to 5 years.   A Swedish study of 665,000 insured dogs in 2014 found an incidence, based on claims of 18/10,000 or 0.18%, which is much lower that the estimated risk.  It named the Boxer as having the highest risk at only 0.61% and also named the CKCS as one of the other affected breeds but I have no percentages.  We know that males are at higher risk than females, that the median survival time is 1.5 years and that pet dogs do better than dual purpose dogs, like those used for hunting, shepherding or working.  There is also a study claiming that whole-color CKCS (Rubies and Black and Tans) have an increased inheritance compared to Blenheim and Tricolors but this is from a 1960 study quoted in a report from 2005.  A 2012 study ruled out an association between Chiari-like malformation or ventriculomegaly and seizures in the CKCS.

Determination of an appropriate treatment regimen for canine epilepsy depends on an accurate diagnosis of the type and cause of seizures, only after which appropriate therapeutic options can be identified.  Early diagnosis is important and should involve a canine neurology specialist to start early antiepileptic care.  Treatment aims to reduce the number and severity of seizures and increase the quality and duration of life.

The mainstay of past anti-seizure control has been oral phenobarbital and or potassium bromide but Levetiracetam (Keppra), Gabapentin (Neurontin) and Pregabalin (Lyrica) have shown great promise and effect. This could fill another article on treatment.

One of the lessons learned was that although it is a serious disease, Canine Epilepsy may affect our beloved Breed less than feared and much more needs to be learned.  The American Cavalier King Charles Spaniel Club – Charitable Health Trust is an organization supporting the research into problems like this.  Learn more at ACKCSC.org.  They are preparing a second Health Survey for Members, which may give us more insight on the incidence of Epilepsy in the CKCS.

Learn more at:

https://www.akcchf.org/canine-health/top-health-concerns/epilepsy/AKCCHF-Understanding-Canine-Epilepsy-2017.pdf
https://www.akc.org/expert-advice/dog-breeding/canine-epilepsy-myths/
https://www.thekennelclub.org.uk/health-and-dog-care/health/health-and-care/a-z-of-health-and-care-issues/epilepsy/
https://www.cavalierhealth.org/epilepsy.htm#:~:text=A%20form%20of%20epilepsy%2C%20called%20%22idiopathic%20epilepsy%27%2C%20is,and%20is%20prevalent%20in%20cavalier%20King%20Charles%20spaniels.

A cohort study of epilepsy among 665,000 insured dogs: incidence, mortality and survival after diagnosis.  L Heske, A Nødtvedt, K Hultin Jäderlund, M Berendt, A Egenvall Vet J. 2014 Dec;202(3):471-6. doi: 10.1016/j.tvjl.2014.09.023. Epub 2014 Oct 13.

Neurological diseases of the Cavalier King Charles spaniel.  Rusbridge, C. J Small Animal Practice, June 2005, 46(6): 265-272.

The association between Chiari-like malformation, ventriculomegaly and seizures in cavalier King Charles spaniels. C.J. Driver, K. Chandler, G. Walmsley, N. Shihab, H.A. Volk. Vet. J.  Feb. 2013;195(2):235-237.