Knowlton A. Reynders, Highwood Norwich
Published in Dog News, The NNT News, and Norwich Notes and Banta
I was asked to address the topic of epilepsy and seizures in our breed. Perhaps the best way to transmit the information I have accumulated is to answer the most frequently asked questions about the disease. My answers are based on the many articles, columns, and veterinary publications I have read. They also reflect conversations I have had with other breeders, with owners of afflicted dogs and puppies, and general research of cases with help from my local veterinarian.
In Seizures and Epilepsy in Dogs, Dr. A. Parker defines canine epilepsy as "a state of repeated, intermittent seizures. A seizure is an external manifestation of an intermittent massive electrical abnormality in the brain." When one speaks to a veterinarian about a definition of canine epilepsy, he classifies the seizures in two categories: Those that are produced by demonstrable diseases, best called acquired, or secondary seizures; and those seizures for which no cause can be determined. The latter are categorized as idiopathic, and are the most common form. Typically, they begin between the ages of six months and five years. There is a higher incidence of idiopathic seizures in males. An acquired seizure can be the result of such metabolic extra cranial diseases as hepatic encephalopathy or hypoglycemia or of such intracranial diseases as encephalitis, brain tumor, head trauma, hydrocephalus, or neurotropic toxins -- a fancy term for insect sprays or other poisons.
Any of the listed affectations can occur alone or in combination, depending on what parts of the brain have been involved:
Speaking with owners and breeders and my local veterinarian, I have collected some examples of lighter episodes: "Very tense, tight shake. Unable to walk, although might try, but have extended steps and are uncoordinated, sometimes going down on rear legs or front. They do not fall over, paw, froth, or get sick. Eyes appear wide and frightened." (From correspondence.) "Jaw could be pried open. There was rapid heartbeat and a body tenseness. No loss of bladder control or defecation. The seizure lasts a minute or two. These light seizures occur in the middle of sleep, walking from one room to another, in the middle of an argument--in the middle of a meal. There is no boundary for time or place of seizure incident."
These are accepted overviews about seizures: Dogs do not suffer during a seizure -- their actions are involuntary; a dog should not be moved during a seizure, except to ensure his safety; dogs on anticonvulsant medication enjoy a normal life expectancy; once stabilized, some dogs can be weaned off of their medication; and, if a seizure lasts longer than ten minutes, call your veterinarian immediately.
There was a very good article, most aptly entitled "Inheritance and Idiopathic Canine Epilepsy", by James G. Cunningham, DVM, PhD and George C. Farnbach, VMD, PhD, published in the July/August 1988 Volume of the Journal of the American Animal Hospital Association. The article described a study that bred selectively using epileptic stock and traced the incidence of the disease through four generations, watching where the epilepsy most commonly occurred. The authors concluded "genetic mechanisms play an important role in transmission of some and possibly most cases of idiopathic canine epilepsy, although the mechanism for this inheritance is not yet known. Until the genetic mechanisms involved are more clearly delineated, the authors recommend that veterinarians advise owners of dogs with idiopathic epilepsy that 1) the idiopathic form of canine epilepsy may have a major genetic component; 2) it generally is impossible without considerably more test breedings to determine the degree of involvement of either dam or sire in producing epileptic offspring; 3) it is unwise to breed an epileptic dog or repeat the breeding that produced it and it is unwise also to breed its littermates."
From my discussions with several veterinarians, owners, and breeders, here are some thoughts that could perhaps benefit Norwich breeding in the future: If a dog has a seizure of any kind, take him to the vet for a complete physical examination, including a blood test. Try to determine if it was a disease-related seizure. And be sure to check for toxins around the house, and have them analyzed as well. A dog may have epilepsy for genetic reasons or may have acquired it through a disease -- which could itself be a genetic problem. As a veterinarian told me, "Epilepsy is a diagnosis of elimination -- elimination of all other causes of the seizures." If you can find no external reason for the seizures and they continue, you have idiopathic epilepsy, and you must look for its origin to your genetic input. If you discover suspect seizures in a bitch or dog you are breeding or in its background, do some serious checking into previous breedings and litters. Don't take chances. The heartbreak occurs when unknowledgeable breeders fail to recognize danger signs, fail to heed the concerns reflected to them by worried owners, and continue to breed.
Since some cases of epilepsy do not arise until the dog is five years of age, it is understandable that a caring breeder could unwittingly produce several litters from an afflicted dog, with no idea that the litters were potentially affected. But it is another thing for a breeder who has been made aware of the problem to make his own determinations on the nature of the problem -- and to continue to breed the dog.
Dr. Parker states "Dogs with seizures due to diseases other than epilepsy are given specific treatment for their disease. They may also be given an anti-convulsant." Epileptic dogs are treated with anticonvulsants. But Dr. Parker further cautions, "If the seizures are mild and occur singly and less frequently than one every two months, the side effects of the drug may outweigh the benefits of seizure control." The owner and the veterinarian must determine the risk/benefit component of anticonvulsant treatment. In fact, only 60 to 70 percent of known cases of epilepsy are controlled. The following drugs are used in the control of canine epilepsy: Diphenyl hydantoin (Dilantin); primidone (Primidone, Mylepsin); and phenobarbital and diazepam (Valium). And, less commonly: Valproic acid (Depakene); paramethadione (Paradione); ethosuximide (Zarontin) and carbamazepine (Tegretol). Dr. Parker also mentions progesterone's and even indicates that acupuncture has been used. The article goes on to list some of the side effects, temporary or long-term, that can accompany treatment with these anti-convulsant drugs: Drowsiness; clumsiness; hyper-excitability; loss of appetite; increased thirst; and excessive urination.
Scottie cramp is described in an article entitled "'Cramp' in Norwich" by Jean Gledhill, appearing in the April 1985 Dog World Breed Notes, which I paraphrase here: The bitch began to manifest symptoms at two and one-half, after her first litter, by going stiff in her hindquarters. She remained conscious, but the muscles in her thighs were knotted and tight. I massaged the affected muscles until the rigidity dissipated; it took about six minutes. She seemed perfectly normal afterward. Several attacks occurred over the next few months, and, after particularly severe attacks, she would vomit. The veterinarian recommended that Vitamin E and selenium be added to her diet. I fed her the Vitamin E and seaweed meal, which contains selenium, and the incidents subsided: One attack in the next ten months, one further attack eleven months after that, and then clear.
Ms. Gledhill equates "Scottie cramp" to human cramping and explains it as the body's inability to deal with the build-up of lactic acid in the muscles. The human body gets rid of the acid by sweating or urinating, allowing more oxygen to get to the muscles. The author notes, "It has been suggested that Vitamin E helps by being a transport system for lactic acid's removal via urine and that the selenium acts as a catalyst for the removal process." Jean Gledhill maintains a catalogue of dogs with this disorder. I have found no other documentation of this disorder in Norwich.
I hope that, in some small way, this article has given you some information about seizures. I feel very strongly that we have it, visibly and less visibly, in many lines of our breeding -- old and new. In fact, no one can say with certainty that one is entirely clear of the problem. The evidence strongly suggests that idiopathic seizures are transferred genetically. And the solution is diligently to breed away from any animal with a history or lineage containing suspicious seizures. Line breeding is an accepted practice, and, if done carefully, has produced fabulous Norwich. If, however, there are seizures in the background on either side, I feel that line breeding multiplies the incidence of genetic carry through. One might end up with an aesthetically perfect dog, but in the process, pass along to the unsuspecting breeder or pet owner the untold miseries of idiopathic epilepsy -- a serious abuse to the future of the breed. I have tried to approach the broad issue of epilepsy in Norwich fairly and objectively. I hope that the publication of what I have learned to date will help to enlighten all of us who care about the breed.
Also see
EPILEPSY in NORWICH
An Update
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