Assessment of the prevalence and clinical features of cryptogenic epilepsy in dogs: 45 cases (2003-2011).

OBJECTIVE: To determine the prevalence and clinical features of cryptogenic epilepsy among dogs.
DESIGN: Retrospective case series. ANIMALS: 214 client-owned dogs with onset of epileptic seizures at ≥ 7 years of age. PROCEDURES: A diagnostic imaging database was searched for dogs with symptomatic or cryptogenic epilepsy. Signalment, seizure history, and diagnostic information were recorded. Information regarding seizure frequency, administration of antiepileptic drugs (AEDs), owners' perceptions regarding quality of life, survival times, and causes of death for dogs with cryptogenic epilepsy was obtained via questionnaire. Variables were compared among dogs grouped according to diagnosis and age.
RESULTS: 45 (21%) dogs had a diagnosis of cryptogenic epilepsy, and 169 (79%) had symptomatic epilepsy. In dogs 7 to 9 years and ≥ 10 years of age at the time of seizure onset, 31 of 106 (29%) and 14 of 108 (13%), respectively, had a diagnosis of cryptogenic epilepsy. At last follow-up, most (40 [89%]) dogs with cryptogenic epilepsy were receiving ≥ 1 AED. Thirty-one of 37 (84%) dogs typically had ≤ 1 seizure/mo following hospital discharge. Death was confirmed in 20 (44%) dogs with cryptogenic epilepsy and was related to seizures or AEDs in 7 Median survival time from onset of seizures was 52 months for all dogs with cryptogenic epilepsy. Median quality-of-life score (scale, 1 [poor] to 10 [excellent]) indicated by 34 owners of dogs with cryptogenic epilepsy was 10 before diagnosis and initiation of AED treatment and 8 afterward. CONCLUSIONS AND CLINICAL RELEVANCE: Cryptogenic epilepsy was diagnosed in a substantial proportion of dogs with an onset of epileptic seizures at ≥ 7 years of age. Seizure control was considered acceptable in most dogs.