Complex partial seizures with orofacial involvement in 35 cats: MRI changes, cerebrospinal fluid analysis, voltage-gated potassium channel antibodies and survival

ObjectivesThe objective of this study was to evaluate the occurrence of voltage-gated potassium channel (VGKC) antibodies and the pattern of MRI changes in cats with complex partial seizures with orofacial involvement (CPSOFI), as well as to investigate whether there are factors influencing survival that could be used as prognostic markers in those cats.MethodsCats with CPSOFI were identified retrospectively. The following data were retrieved from the hospital database: signalment, age at first seizure and presentation, the presence of antibodies against VGKC (leucine-rich glioma inactivating factor 1 (LGI1), contactin-associated protein 2 (CASPR2)) and cerebrospinal fluid (CSF) analysis findings. Brain MRI scans were evaluated for T2 and/or fluid-attenuated inversion recovery (FLAIR) hippocampal hyperintensity and hippocampal contrast enhancement by a radiologist. The correlation between being positive for VGKC antibodies and MRI hippocampal hyperintensity was investigated.ResultsSerum antibodies against VGKC were found in 31.4% of cats, with 10/11 positive cats having antibodies against LGI1 and 1/11 against CASPR2. MRI T2/FLAIR hippocampal hyperintensities and T1 contrast enhancement were seen in 57.1% and 27.1% of cats, respectively. There was a weak correlation between those antibodies and MRI changes (phi coefficient 0.12). The following factors did not influence survival on multivariable regression analysis either for all cats together or when the cats that died were evaluated separately: age at first seizure, breed, sex, T2/FLAIR hippocampal hyperintensity, being positive for VGKC antibodies and prednisolone treatment.Conclusions and relevanceThere are no consistent findings on MRI or on testing for VGKC antibodies in all cats with CPSOFI. None of the factors investigated can be used to predict outcomes.