Epilepsy :
It happened without warning. One moment my young male Belgian Tervueren was snuggling against me as I sat on the couch; the next moment he lost control of his hindquarters and fell onto his side, unconscious. His lips writhed back over his teeth; his legs stretched out, then became rigid; and his head twisted up and back as if an unseen hand was trying to raise his chin to an impossible height. It seemed like an eternity, but actually only two minutes passed before his body relaxed and consciousness slowly ebbed back. For an hour afterward he seemed exhausted and disoriented. I was shaken too, never having witnessed such a seizure before. Yet later that day the dog was romping about as if nothing out of the ordinary had occurred.
My dog is lucky. His seizures have been few and far between. We now believe they are caused by hypothyroidism. Other dogs are not so lucky. Seizures can be severe and frequent. They may occur in "clusters" (several in one day), or progress to the life-threatening state of status epilepticus. In extreme cases where seizures cannot be controlled, a veterinarian may advise euthanasia.

Epilepsy is found in all breeds and mixed breeds of dogs. Belgian Tervueren are listed among the breeds for which a genetic factor is either proved or highly suspected. Other breeds so listed include the Beagle, Dachshund, German Shepherd Dog, (Alsatian), and Keeshond. A high incidence of seizure disorders is also found in Boxers, Cocker Spaniels, Border Collies, Golden Retrievers, Irish Setters, Labrador Retrievers, Miniature Schnauzers, Poodles, Saint Bernards, Siberian Huskies, and Wire-Haired Terriers. (Oliver, Seizures). The prevalence of epilepsy in the general dog population has been estimated at .5 to 5.7%. (Koestner, Cunningham).
A progress report on the epilepsy survey conducted by the American Belgian Tervuren Club in cooperation with John Oliver, Jr., DVM in 1983 found that 57 (21%) of the 268 Tervueren studied had suffered more than one seizure. The authors of that report concluded, "At this time, we believe there is sufficient evidence for the probable genetic basis of seizures in Tervuren to warrant concern on the part of breeders". (Mahaffey). Unfortunately, this survey was discontinued.

The term "epilepsy" can be confusing because some authors use it to describe recurrent seizures of any etiology (cause), while others use it to specify recurrent seizures unrelated to brain disorders or underlying disease processes. (Shell, Understanding). The definitions below are helpful in distinguishing types of epilepsy.

Types of Epilepsy :

Primary epilepsy: also known as idiopathic, genetic, inherited, or true epilepsy. There are no positive diagnostic findings that will substantiate the diagnosis. It is a case of ruling out every other possibility. The first seizure in a dog with primary epilepsy usually occurs between the ages of 6 months and 5 years. (Oliver, Seizures). However, a diagnosis of primary epilepsy is not proof of a genetic defect; only careful breeding studies could prove that. The breed, the age, and the history may suggest a genetic basis for primary epilepsy if there is a familial history of seizures.

Secondary epilepsy :refers to seizures for which a cause can be determined, and there are many. In dogs less than one year of age, the most commonly-found causes of seizures can be broken down into the following classes: degenerative (storage diseases); developmental (hydrocephalus); toxic (lead, arsenic, organophosphates, chlorinated hydrocarbons, strychnine, tetanus); infectious (distemper, encephalitis, and others); metabolic (such as transient hypoglycemia, enzyme deficiency, liver or kidney failure); nutritional (thiamine, parasitism); and traumatic (acute injury). In dogs 1-3 years of age, a genetic factor is most highly suspected. In dogs 4 years of age and older, seizures are commonly found in the metabolic (hypoglycemia, cardiovascular arrhythmia, hypocalcemia, cirrhosis) and neoplastic (brain tumor) classes. (Oliver, Seizure). Dr. Jean Dodds has mentioned that seizures are also associated with hypothyroidism, which is a familial (inherited) autoimmune disease of purebred dogs.