Epilepsy in dogs five years of age and older: 99 cases (2006-2011)

Objective-To classify the etiology of epilepsy and evaluate use of abnormal neurologic examination findings to predict secondary epilepsy in dogs >= 5 years of age. Design-Retrospective case series. Animals-99 dogs with epilepsy. Procedures-Medical records were reviewed to identify client-owned dogs evaluated for seizures at >= 5 years of age with a diagnosis of primary or secondary epilepsy. Dogs were stratified by age; prevalence of primary and secondary epilepsy and the proportion of dogs with secondary epilepsy that had a diagnosis of neoplasia (on the basis of MRI findings) versus other disease were evaluated. Sensitivity and specificity of abnormal neurologic findings to detect secondary epilepsy were determined. Results-7 of 30 (23%) dogs 5 to 7 years of age, 13 of 29 (45%) dogs 8 to 10 years of age, 13 of 33 (39%) dogs 11 to 13 years of age, and 2 of 7 dogs >= 14 years of age had primary epilepsy. Prevalence of primary vs secondary epilepsy did not differ among age groups. The proportion of dogs with neoplasia at 5 to 7 years of age was lower than that of dogs in other age groups. Abnormal neurologic examination results had 74% sensitivity and 62% specificity to predict secondary epilepsy. Conclusions and Clinical Relevance-A substantial proportion of dogs >= 5 years of age had primary epilepsy. Results indicated that lack of abnormalities on neurologic examination does not exclude the possibility of intracranial lesions, and MRI with CSF analysis (when applicable) should be recommended for all dogs with onset of seizures at >= 5 years of age.