Epilepsy is a disorder causing sudden, recurring seizures. It's one of the most common neurological disorders in dogs, though there's no hard data about how prevalent it is. According to the Canine Epilepsy Network, some studies estimate as many as 4 percent of all dogs are affected.
Types of Epilepsy
Any dog can have epilepsy, and the causes can vary widely. Viral, fungal and bacterial infections, brain malformation, trauma, tumors, disease such as liver disease and hypoglycemia, and presence of toxins can all trigger repeated seizures. About 80 percent of the time, epilepsy is idiopathic, meaning there's no physical reason to be found for the episodes. Idiopathic epilepsy can have a genetic basis in many dog breeds and be familial, meaning it is prevalent in certain lines or families of animals. The Canine Epilepsy Network notes "some families may have up to 14 percent epileptics."
Any dog can have a seizure if a "seizure threshold" is crossed by too much activity in the brain. Many of the idiopathic forms of epilepsy are inherited -- caused by a mutation of a gene inherited from a dog's parents. The mutated gene causes certain cells to be more excitable and able to cross the seizure threshold causing seizures, which is speculated to be the root of hereditary epilepsy. Canine Epilepsy Network reports a few breeds have proven hereditary epilepsy and it's suspected to occur in numerous other breeds. A great deal has yet to be learned about canine epilepsy, but it's believed there are different modes of inheritance and various genes at play in different dog breeds and families.
Breeds Prone to Epilepsy
Breeds prone to inherited epilepsy include German shepherds, beagles, Belgian Tervurens, dachshunds and keeshonds. Collies, golden retrievers, poodles, Siberian huskies, cocker spaniels, Irish setters, miniature schnauzers, wire-haired fox terriers, Labrador retrievers and Saint Bernards have a high incidence of idiopathic epilepsy, but inheritance has yet to be proven. The characteristics of genetic epilepsy tend to show up between 10 months and 3 years of age, but dogs as young as 6 months or as old as 5 years can show signs. If your pup is one of the breeds on the list, it doesn't mean he'll develop epilepsy. As well, just because he's not one of the vulnerable breeds doesn't mean he won't experience seizures. Mixed breed dogs also can have epilepsy.
If your dog experiences seizures, he'll likely fall on his side and become stiff. Activity during a seizure includes vocalization, salivation, urination and defecation, as well as paddling with all four legs. The seizures can last between 30 and 90 seconds and usually occur while the dog's resting or asleep. It can take up to 24 hours for a dog to recover fully from a seizure. Treatment of idiopathic epilepsy usually entails anti-epileptic drugs, though to date, no medication has eliminated seizures. Generally, if a dog suffers more than 10 or 12 seizures a year, medication is prescribed as treatment.