Seizures in Cats

Prevalence of idiopathic feline epilepsy has probably been overestimated because of inconsistent use of MRI or postmortem examination (PME) to definitively rule out structural brain disease. Feline hippocampal necrosis (FHN) has been proposed asa possible structural cause of seizures in cats. This retrospective study evaluated the prevalence and clinical course of feline epilepsy of unknown cause (EUC) using MRI and/or PME to rule out structural disease. Records of 81 client-owned cats were examined. All had undergone MRI or PME. Structural brain lesions were detected in 38 cats; significant metabolic or toxic abnormalities were found in 25 cats. FHN was confirmed in 1 cat. Seizure cause remained undefined in 18 cats, suggesting EUC. Of these 18 cats, focal or focal onset seizures were identified in 9 and generalized seizures were reported in the remaining 9. Cats with EUC were more likely to present with focal seizures than cats with structural, metabolic, or toxic causes of seizures. One-year survival rate of cats with EUC was 73%, compared with 35% for cats with structural epilepsy or toxic/metabolic diseases. Eight cats with EUC achieved seizure remission, which was maintained with (n = 5) or without (n = 3) antiepileptic drugs. Prevalence of true idiopathic epilepsy in study cats is much lower than previously reported, but long-term prognosis is better than in dogs and humans. A full diagnostic workup with advanced imaging should be performed on all cats with recurring seizures.

Global Commentary

The use of idiopathic when referring to epileptic conditions has been associated with an underlying genetic cause. In dogs, over 40 breeds have a documented genetic cause of epilepsy. In cats, where domestic short-haired crossbreeds are the most common, idiopathic would seem redundant and/or confusing. This study correctly proposes a shift in the terminology of epileptic cats to adopt the phrase EUC. Based on this study, only 2 of 10 cats with seizures would fulfill the criteria necessary to be labeled in this way, with 8 of 10 cats having an identifiable cause for their seizures. While EUC is less common than in dogs, it seems these cats can have a much better prognosis in terms of lifespan and quality of life; more than 40% go into seizure remission. One subtle message that may get lost in the documentation of the prevalence of EUC is that early and aggressive treatment is essential for successful long-term seizure control.—Simon Platt, BVM&S, MRCVS, DACVIM (Neurology), DECVN

Source

Clinical characterization of epilepsy of unknown cause in cats. Wahle AM, Brühschwein A, Matiasek K, et al. JVIM 28:182-188, 2014.

This capsule is part of the WSAVA Global Edition of Clinician's Brief.