Survival of Epileptic Dogs

Long-term outcome of dogs with epilepsy is poorly documented. This study investigated survival and prognosis in client-owned dogs with idiopathic epilepsy (n = 78) or with epilepsy with a known intracranial cause (n = 24). Selected risk factors that may influence survival time and duration were investigated. The study was retrospective and hospital-based and included follow-up questionnaires given to owners via telephone. Questions were asked about the dog’s epilepsy and treatment status, whether the patient was still alive, and, when applicable, cause of death. 

Results indicated that dogs with idiopathic epilepsy had a median life span of 9.2 years, close to that reported for dogs in general, compared with 5.8 years for dogs with known intracranial disease. Neutered male dogs with idiopathic epilepsy had a significantly shorter life span than did intact males; it was hypothesized that testosterone may possess anticonvulsant properties. Dogs with epilepsy secondary to inflammatory disease had longer survival times than dogs with epilepsy caused by neoplasia, malformation, or hemorrhagic stroke. 

Therapy with 2 anti-epileptic drugs did not negatively impact survival time. Death/euthanasia related to epilepsy occurred in 52% of dogs, many with histories of cluster seizures and/or status epilepticus. Data from this study may influence how clinicians advise owners about prognosis in epileptic dogs, although certain breed profiles with specific epilepsy phenotypes may not have been represented.

Commentary

This study helps support what veterinary neurologists have been telling clients for years—namely, that idiopathic epilepsy typically does not shorten the patient’s life span. Although a previous study found a significantly shorter life span in dogs with epilepsy-related death,¹ this study found a similar life span as compared with the general canine population. The original study was performed in the late 1990s. It is possible that the longer survival time in this study is related to increased importance of the human–animal bond and to tolerance of the disorder, its treatment, and associated adverse effects of treatment, although this has not been critically analyzed. 

The authors also found that the need to use more than 1 antiepileptic drug (AED) was not linked to poor prognosis. In this study, only 1 dog was on more than 2 AEDs; many epileptic dogs treated by veterinary neurologists are on 3 or more. It would be interesting to know whether specific AEDs are associated with shorter life span and whether patients given higher numbers of AEDs had any difference in life span and epilepsy-associated death. To my knowledge, there are no studies that investigate or describe the actual causes of epilepsy-related death (eg, owner financial constraints, adverse events associated with medications, quality-of-life issues for owners and pets).—Mark Troxel, DVM, DACVIM (Neurology), Massachusetts Veterinary Referral Hospital