Epilepsy is a common brain disorder in companion animals--especially in dogs--characterized by spontaneous seizure activity. Seizures occur with abnormal excitement of the brain's electrical signals and are defined by an aberration in the patient's consciousness or behavior.
Seizures can happen for a wide variety of reasons: low blood sugar, toxins, high fevers, abnormal electrolyte levels, mechanical pressure on the brain after trauma or due to tumors, etc. Epilepsy (also called "idiopathic epilepsy" or, more generically, "undiagnosed seizure disorder") is what we term any seizure-eliciting disease that has no defined cause.
Epileptic dogs can present at any age but most will make their disease known via owner-observed seizure activity before the age of five. The disease is also characterized by varying degrees of severity and amenability to treatment. Some dogs suffering an intransigent form that leads almost inevitably to euthanasia while very mild cases carry an excellent prognosis.
Based on the evaluation of breed and line-specific predispositions to epilepsy, it's clear this disorder is inherited. The mode of inheritance, however, has not been worked out and seems to vary depending on the affected breed. Multiple genes are believed to be involved in some cases.
Symptoms and Identification
Symptoms may vary widely in terms of the length, frequency and general manifestation of the seizures. Some regularity of the seizure activity may be evident but in all cases the timing of the seizures is effectively unpredictable.
Typically, idiopathic epilepsy can be said to have been diagnosed only after all other obvious causes of seizures have been eliminated from the list of possibilities. A physical examination and basic laboratory testing (CBC, chemistry, urinalysis) is required. Toxicology studies, specific testing for infectious diseases and cerebral spinal fluid analysis can be very helpful as well, especially for patients with severe or seemingly progressive symptoms. Advanced imaging studies (MRI or CT scan) are strongly recommended for middle aged to older animals to rule out the possibility of brain tumors or other lesions.
Epilepsy has been seen in all breeds of dogs. Those most affected include:
Idiopathic epilepsy itself is considered untreatable but the disease can be managed with the long-term use of drugs. These medications serve to raise the brain's resistance to the abnormal electrical impulses that trigger seizures.
In dogs the most common drug of choice is phenobarbital but many other choices exist for chronic therapy in the event this drug's side effects prove prohibitive. Unfortunately, almost all other drug choices are significantly more expensive ones. In almost all cases where drug therapy is elected, frequent monitoring of these patients (typically through serial labwork) is necessary.
For more severe sufferers, however, treatment may also include hospitalization to manage more severe episodes during which prolonged seizure activity can lead to life-threatening consequences.
Some dogs, however, may not require any treatment at all. Mild cases may, in fact, be more amenable to suffering the occasional seizure than to risking the side effects of the drugs used to treat them.
The cost of this disease varies drastically depending on the severity of the disease, whether hospitalization is needed and how often, whether they respond to inexpensive drugs or require pricier options and on whether advanced diagnostic testing is necessary.
Diagnosis may reach into the range of thousands of dollars for some, especially for those who require a neurologist's expertise to manage their more complex condition. Typically, however, dogs will do well with simple diagnostics, simple drugs and simple monitoring that may run as low as $200 to $500 a year--more for larger dogs who require larger doses of medication.
More expensive drug choices can mean $500 to $5,000 a year in necessary medication. Euthanasia is often elected in cases where the high end of this range is required to raise an animal's quality of life to a livable level.
There is no known mode of prevention for idiopathic epilepsy save a dedicated breeding program that seeks to eradicate the trait via sterilization of affected animals and as many of its relatives as the possible mode of inheritance suggests is prudent (at least all first degree relatives).
Seizures themselves can often be prevented with veterinary avoidance of specific drugs that may reduce the seizure threshold.
Institute for Genetic Disease Control in Animals Hall, S.J.G., Wallace, M.E. 1996. Canine epilepsy: a genetic counselling programme for keeshonds. Veterinary Record. 138: 358-360.
Chrisman, C.L. 1995. Seizures. In S.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary Internal Medicine, pp. 152-156. W.B. Saunders Co., Toronto.
Parent, J. 1996. Signalment and seizure pattern in the diagnosis and treatment of recurrent seizures. ACVIM-Proceedings of the 14th Annual Vet. med. Forum. p. 326-327.
Canine Inherited Disorders Database