Epilepsy in Cavalier King Charles Spaniels
See also: Flycatcher's Syndrome
-
Symptoms - Diagnosis
- Treatment
- Breeders' Responsibilities
- Current Research
- Related Links
- Veterinary Resources
Epilepsy refers to repeated seizures. Seizures are a sign of brain disease. Idiopathic epilepsy is an inheritable disorder which is prevalent in cavalier King Charles spaniels. It is caused by a mutation in a specific gene which the dogs have inherited from their parents.
According to a report in the June 2005 issue of the Journal of Small Animal Practice, idiopathic epilepsy has been found to occur more frequently in descendants from bloodlines originating from whole-colored CKCS ancestors from the late 1960s, especially from matings of blood relatives, such as half-siblings.
Symptoms
There are many different types of seizures in dogs. The most common is the generalized major motor seizure, characterized by paddling of the limbs. The dog may cry, bark or whine during the seizure, and it may snap or bite, not quite fully aware of its surroundings. Urination and defecation are common during a generalized seizure. Post seizural signs may last from a few minutes to an hour.
The onset of epilepsy in cavaliers is most common between the ages of six months and five years.
The most common form of hereditary epilepsy in cavaliers is flycatcher's syndrome which is discussed on its own webpage.
Diagnosis
Diagnosing epilepsy in dogs is difficult. It begins by attempting to rule out other causes for the seizures. The electroencephalogram (EEG) is a frequently used device in diagnosing epilepsy, but has serious drawbacks in animals. Advanced imaging, such as magnetic resonance imaging (MRI) or CT scans, is necessary to be able to actually see the brain. By imaging the brain, veterinarians are able to diagnose diseases such as brain tumors or hydrocephalus (water on the brain) which can cause seizures. Apart from the EEG or MRI or CT scans, there is no health test for epilepsy.
Treatment
Immediately after a seizure, the dog should be handled with caution. The dog likely will pant after a seizure, due to heat generated by the intense brain activity and seizure. Cool, wet compresses place at the base of the skull and in the groin area will help decrease the body temperature. The dog should be offered a drink of water, but should not be left unattended with a water bowl.
In a 2004 article, Dr. H.C. Gurney of Colorado reports success in treating dogs during epileptic seizures by applying ice directly to the dogs' backs at T10 to L4 of the spine. See the article citation for details and a diagram.
All dogs should be examined by a veterinarian after their first seizure for determination of the cause. Anti-convulsant therapy (usually oral phenobarbital and/or bromide) may be started once the seizures recur frequently. The owner should keep a calendar noting the frequency of the seizures, and the dog that seizures more than once a month should treated long term with anti-convulsants. In some cases, higher powered anti-convulsants, such as levetiracetam (Keppra) or topiramate (Topamax) may be prescribed.
The anticonvulsant gabapentin (Neurontin, Gabarone) is being prescribed, following a study which has shown that between 41% and 55% of dogs have responded to it. Gabapentin works through a receptor on the membranes of brain and peripheral nerve cells. It binds to calcium channels and modulates calcium influx as well as influences GABergic neurotransmission. In humans, gabapentin reportedly does not interact with any other medications, and it is not metabolized, so it is fully excreted in the urine and has no affect upon the liver. However, in dogs, gabapentin is partially metabolized in the liver, and therefore the prescribing neurologist may be expected to order periodic blood tests to check the liver enzymes.
A newer anticonvulsant, pregabalin (Lyrica), is being prescribed by some neurologists. See Current Research. It is closely related to gabapentin and was developed by Pfizer, which also developed gabapentin. Pfizer reports that pregabalin is more potent than gabapentin and achieves its effect at lower doses. Doses of pregabalin also reportedly have a longer lasting effect than gabapentin. No generic version is available, and as an exclusive brand, Lyrica is quite expensive in comparison to generic gabapentin.
A recent study of the use of acepromazine maleate (i.e., acetylpromazine), which is a common sedative administered to dogs, involved administered it for tranquilization during hospitalization to 36 dogs with a prior history of seizures and to 11 other dogs to decrease seizure activity. No seizures were observed within 16 hours of its administration in the 36 dogs that received the drug for tranquilization, and seizures abated for from 1.5 to 8 hours or did not recur in 8 of 10 of the 11 dogs that had been actively seizing. Also, excitement-induced seizure frequency was reduced for 2 months in one dog.
Zonisamide (Zonegram) is an anticonvulsant which in clinical trials appears to be effective for generalized seizures in dogs. exerts. It’s anti-seizure effect is believed to work through sodium and calcium channels. Dr. Curtis Dewey has conducted studies of this drug.
Medication will usually eliminate seizures entirely, and is considered effective if a seizure occurs no more than every four to six weeks. Any time the dog exhibits a cluster of seizures, the veterinarian should be consulted, and may require immediate emergency treatment by the veterinarian, due to the possibility of permanent brain damage.
Breeders' Responsibilities
The Canine Inherited Disorders Database (www.upei.ca/~cidd/intro.htm) recommends that cavaliers which have had seizures should not be bred, nor should their parents and siblings.
Current Research
4December 2009: Pregabalin (Lyrica) is being studied to treat epileptic dogs. Dr. Curtis Dewey, board certified veterinary neurologist at Cornell University's college of veterinary medicine, reports that 78% of dogs respond to pregabalin (Lyrica) and that there was a 57% mean reduction in seizures for the participants who finished the study; all had been diagnosed with difficult-to-control seizures. For more details, go here.
4The Canine Epilepsy Project, led by Dr. Ned Patterson, of the University of Minnesota's College of Veterinary Medicine, and by Dr. Gary Johnson, of the University of Missouri's College of Veterinary Medicine, is a collaborative study into the causes of epilepsy in dogs. Its goal is to find the genes responsible for epilepsy in dogs so that wise breeding can decrease the incidence of the disease in dogs, and that, knowing what genes regulate epilepsy in dogs may help better tailor therapy to the specific cause. Participation by owners of affected dogs and their relatives is essential to the success of this project. Researchers need DNA samples from dogs who have experienced seizures, and immediate relatives, both normal and affected. Specifically, they need samples from all available siblings, parents, and grandparents. If the affected dog has been bred, all offspring and mates should be sampled as well. Useful research families are explained in more detail here. Participation in this research project is confidential - the names of individual owners or dogs will not be revealed. Data and DNA sample collection instructions and sample submission forms are available on www.canine-epilepsy.net, or the packet will be mailed or faxed upon request. Contact Liz Hansen, at the Animal Molecular Genetics Laboratory, University of Missouri - College of Veterinary Medicine, email hansenl@missouri.edu
4Profs. Chris Rundfeldt, Andrea Tipold, Wolfgang Loscher, and others, of the Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, and Center for Systems Neuroscience, Hannover, Germany, have researched, developed, and have been studying the efficacy of a new antiepileptic and anxiolytic drug, ELB138, which is a low-affinity partial BZD-receptor agonist, formerly called AWD 131-138; 1-(4-chlorophenyl)-4-morpholino-imidazolin-2-one. They and others hold a U.S.patent (20050070537) for this drug. They report that "the reduction in seizure frequency using ELB138 in dogs with newly diagnosed idiopathic epilepsy was comparable to the reduction in dogs treated either with phenobarbital or primidone. In dogs with chronic epilepsy and add-on therapy with either ELB138 or potassium bromide, such supplementation reduced the seizure frequency and the duration and severity of seizures" with reportedly rare side effects.
Related Links
Questions for Breeders
Flycatcher's Syndrome
Canine Inherited Disorders Database
Veterinary Resources
Control of Canine Genetic Diseases. Padgett, G.A., Howell Book House 1998, pp. 198-199, 235.
A Simple,
Effective Technique for Arresting Canine Epileptic Seizures. H. C.
Gurney, Janice Gurney. J. Amer. Holistic Vet.
Med. Assn. Jan 2004; 22(4):17-18.
Quote: "Fifty-one epileptic canine patients were successfully treated during an
epileptic
seizure with a technique involving the application of ice on the back
(T10 to L4). This technique was found to be effective in aborting or shortening
the duration of ictus. ...
Ice is applied as soon as the seizure is observed. The application itself
is either a block of ice (i.e., water frozen in a metal ice tray, with the tray
applied directly to the seizing patient), or ice (cubes or crushed ice in a
plastic bag). The ice is held firmly to the dog’s back, on the area superior to
the spinal process from T10 (palpable at the 'low spot' on the canine spine) to
L4 (Figure at right). The size of a given ice application is sufficient to cover the
described area. Maintain firm pressure in that location until the patient
spontaneously recovers sternal recumbency and makes efforts to rise and walk. If
the patient is prone to 'chain' episodes or displays evidence of returning to
ictus after removal of the ice, the ice should once again be applied until the
patient regains sternal recumbence (when chain seizures occur, aggressive
medical intervention is necessary). Clients have used bags or boxes of frozen
vegetables, but such applications are reported to be less effective.
... The sooner ice was applied during an epileptic event, the more effective the
intervention was in stopping or abbreviating the seizure. Also of note was the
observation that the canines’ post-ictus recovery time was shorter, and recovery
appeared to be augmented."
Inheritance of occipital bone hypoplasia (Chiari type I malformation) in Cavalier King Charles spaniels. Rusbridge C., Knowler S. P.; J. Vety. Int. Med. 18, 673-678 (2004)
"Seizures" (Podell, M.) in: Manual of Small Animal Neurology, 3d ed. Editors Olby N., Platt S., British Small Animal Vety Assn (2004). pp 97-112.
Anticonvulsant efficacy of the low-affinity partial benzodiazepine receptor agonist ELB 138 in a dog seizure model and in epileptic dogs with spontaneously recurrent seizures. Loscher W, Potschka H, Rieck S, Tipold A, Rundfeldt C. Epilepsia. 2004 Oct;45(10):1228-39.
Neurological diseases of the Cavalier King Charles spaniel. Rusbridge, C. J Small Animal Practice, June 2005, 46(6): 265-272(8). "Idiopathic epilepsy is a inheritable disease in the CKCS and is seen in all colour varieties but is more frequent in lines originating from whole-coloured ancestors from the late 1960s, especially where there were half-brother/sister matings (Rusbridge and Knowler 2004). Diagnosis is by ruling out other causes of seizures; for example, using haematology and biochemistry to rule out reactive causes such as hepatic encephalopathy, and MRI and CSF analysis to rule out structural and inflammatory disease such as GME. The author’s firstline therapy is phenobarbital or bromide monotherapy, progressing to a combination of both drugs if the seizures are not adequately controlled. Some cases of CKCS epilepsy are difficult to control and novel anticonvulsants such as levetiracetam (Keppra; UCB Pharma) or topiramate (Topamax; Janssen-Cilag) may be useful. For a more extensive review of the management of epilepsy see Podell (2004)."
Anticonvulsant activity and tolerance of ELB138 in dogs with epilepsy: A clinical pilot study. Rieck S, Rundfeldt C, Tipold A. Vet J. 2005 May 16.
A Retrospective Study on the Use of Acepromazine Maleate in Dogs With Seizures. Karen M. Tobias, Katia Marioni-Henry, and Rebecca Wagner. J. Am.An. Hosp. Assn. (2006) 42:283-289.
Epil-K9's Canine Epilepsy Resources website: www.canine-epilepsy.com/Resources.html
Pregabalin as an adjunct to phenobarbital, potassium bromide, or a combination of phenobarbital and potassium bromide for treatment of dogs with suspected idiopathic epilepsy. Curtis W. Dewey, Sofia Cerda-Gonzalez, Jonathan M. Levine, Britton L. Badgley, Julie M. Ducoté, Gena M. Silver, Jocelyn J. Cooper, Rebecca A. Packer, and James A. Lavely. JAVMA, Dec 2009; 235(12):1442-1449, Quote: "Objective—To assess tolerability and short-term efficacy of oral administration of pregabalin as an adjunct to phenobarbital, potassium bromide, or a combination of phenobarbital and potassium bromide for treatment of dogs with poorly controlled suspected idiopathic epilepsy. ... Animals—11 client-owned dogs suspected of having idiopathic epilepsy that was inadequately controlled with phenobarbital, potassium bromide, or a combination of these 2 drugs. ... Results—Seizures were significantly reduced (mean, 57%; median, 50%) after pregabalin administration in the 9 dogs that completed the study; 7 were considered responders with mean and median seizure reductions of 64% and 58%, respectively. Adverse effects for pregabalin were reported in 10 dogs. Mean and median plasma pregabalin concentrations for all dogs were 6.4 and 7.3 μg/mL, respectively. Conclusions and Clinical Relevance—Pregabalin may hold promise as a safe and effective adjunct anticonvulsant drug for epileptic dogs poorly controlled with the standard drugs phenobarbital or potassium bromide. Adverse effects of pregabalin appeared to be mild. Additional studies with larger numbers of dogs and longer follow-up intervals are warranted."
Breed Predispositions to Disease in Dogs & Cats (2d Ed.). Alex Gough, Alison Thomas. 2010; Wiley-Blackwell Publ. 53.
