Canine epilepsy

Epilepsy is one of the most common neurologic diseases in dogs. It generally starts in dogs 6 months to 5 years of age, most usually at the age of 2 to 3 years.

The main symptom of epilepsy is repeated seizures. Seizures are the result of a disturbance in the electrical activity of brain cells and are usually unpredictable. They may be triggered by specific events such as stress or appear at regular intervals with no apparant reason. The term epilepsy is applicable only if the seizures repeat again and again over a period of time with no underlying disease process.

There is no test to diagnose epilepsy per se, so veterinarians have to rely on a diagnosis per exclusionem, i.e. by elimination of other possible underlying diseases. It is therefore important to provide as much information as you can, such as what your dog looks like when he is having seizures, how long the seizures last, and whether the signs were more pronounced on one side of your pet, or not. Your veterinarian will probably also want to know if your dog has fever, was exposed to toxins or recently vaccinated.

Seizures usually consist of three phases:
During the pre-seizure phase (also called aura or prodrome) the dog will commonly show a change in behaviour such as hiding, withdrawing or attention-seeking for hours or even days before a seizure. Minutes before the actual seizure begins your dog may start salivating or whining.

The seizure itself is called ictus. It usually starts with a tonic part during which there is a stiffening of the muscles causing the dog to fall to their side. This tonic phase is usually very brief (less than 30 seconds) and followed by rhythmic movements (the clonic part). Your dog may appear excited, vomit, salivate, run in circles, collapse, and have uncoordinated muscle activity. This stage generally lasts less than 5 minutes.

After the seizure (Post-Ictal Phase), your pet may seem disoriented, uncoordinated, and occasionally blind (temporary) or show Abnormal behaviour associated with fatigue, depression, hunger, thirst, or hyperactivity. This may last several minutes to days.

Epilepsy affects around 5 % of the dogs. However, some breeds have a higher tendency to develop epilepsy and show evidence for an inherited basis. These breeds are: Belgian tervueren, Golden and Labrador Retrievers, German shepherd, Cocker Spaniel, Collie, Keeshond, Poodle, Miniature Schnauzer, Irish Setter.
It is recommended that dogs with epilepsy (and their parents and siblings) should not be used for breeding, since this tendency can be passed through the generations.

References and Further Reading:

Canine Epilepsy Network: Understanding Your Pet's Epilepsy
Epilepsy and Seizures
Epilepsy by Canine Inherited Disorders Database