Primary Epilepsy in Dogs

Any type of disease in a dog is devastating for a pet owner. The disease can also be scary if the primary side effect is seizures and the owner does not know what is causing them or how to treat them. The main disease that affects dogs in this manner is epilepsy, of which there are three types: primary, secondary and reactive. Most young dogs who suffer from seizures have primary epilepsy.

  1. Identification

    • Primary epilepsy has no underlying structural cause. This means there is nothing else the dog is suffering from that can explain the dog's seizures. Causes for secondary or reactive epilepsy include tumor, infection, trauma, hydrocephalus, low blood sugar, low calcium, liver failure, toxins, kidney failure and electrolyte abnormalities. The absence of these symptoms tells doctors that the epilepsy is primary, caused by genetics rather than an outside trigger.

    Significance

    • According to Ned Patterson, D.V.M., between 0.5 and 5 percent of dogs develop epilepsy in their lifetime, and primary epilepsy is responsible for 65 percent of seizures that occur in dogs between the ages of 1 and 5. Breeds that are genetically inclined to the disease are beagles, dachshunds, German shepherds, keeshonds, and Belgian tervurens.

    Diagnosis

    • A veterinarian diagnoses primary epilepsy by excluding causes that signify secondary or reactive epilepsy. Also, for a proper diagnosis, a dog must exhibit multiple seizures, with no known cause, and act normal between seizures. A seizure that affects a dog with primary epilepsy affects the whole body and is both tonic and clonic (increases muscle tone and movement).

    Cause

    • Primary epilepsy is thought to be caused by an imbalance of excitatory and inhibitory signals in the brain. Glutamate is an excitatory chemical signal in the brain that lets calcium and sodium move through brain channels. Gamma amino butyric acid (GABA) is a major inhibitory chemical signal that lets chloride into cells and potassium out. Too much glutamate or not enough GABA chemical signals can trigger seizures in dogs, as well as not being able to properly transfer calcium, sodium, chloride and potassium. This genetic defect points to primary epilepsy.

    Treatment

    • Anti-epileptic drugs (AEDs) can treat dogs with primary epilepsy. Ideally, this type of drug with end a dog's seizures without causing negative side effects, but this is only the case for about 50 percent of patients. Realistically, the AED will decrease the instances and duration of a dog's seizures. Once a dog's seizure pattern is established, it is determined whether or not an AED is the correct path for treatment. Phenobarbitol is the number one recommended AED, but it has side effects such as increased thirst, appetite and a short period of sedation. It can also cause liver damage. Potassium bromide can be used along with phenobarbitol. It's side effects include sedation and pancreatitis. Veterinarians do not recommend these drugs for dogs that suffer seizures less than once every two months to avoid the risks of these side effects.