Semiological and etiological classification of seizures in cats and dogs: 53 cases

Epileptic seizures in cats and dogs are etiologically classified as idiopathic epilepsy, structural epilepsy and reactive seizures, and semiologically as atonic, tonic/clonic, or generalized tonic clonic, focal and focal seizures evolving into generalized seizures. This retrospective study aimed to evaluate the semiological patterns and etiological causes of seizures in both species, and to assess interspecies differences in a regional veterinary population. Between January 2022 and January 2025, 77 cats and 106 dogs presented with seizures to Ondokuz Mayis University Animal Hospital (Samsun/Turkiye). After exclusions due to insufficient data or financial constraints, 24 cats and 29 dogs were included based on the Tier-I diagnostic criteria proposed by the International Veterinary Epilepsy Task Force. The relationships between species, age, sex, neuter status, seizure semiology and etiology were analyzed. Generalized tonic-clonic seizures were observed in 83.3% of cats and 72.4% of dogs. Idiopathic epilepsy was diagnosed in 41.7% of cats and 55.2% of dogs. Structural epilepsy in cats was mainly associated with feline infectious peritonitis, while canine distemper virus was the predominant cause in dogs. Although seizure types were broadly similar across species, some etiological differences appeared regionally. The high rate of generalized seizures may reflect observer bias or challenges in accurately classifying semiology without electroencephalography. This study highlights the utility of tiered diagnostic approaches in veterinary epileptology and underscores the need for updated, species-specific consensus guidelines for diagnostic approach and classification especially in feline patients.