Bilateral tonic–clonic seizure and focal cortical hyperexcitability in familial Creutzfeldt‐Jakob disease with E200K mutation of the prion protein

Abstract Convulsive epileptic seizures are rare in Creutzfeldt‐Jakob disease (CJD), and their clinical and EEG features have not been reported in detail. We describe a case of familial CJD with an E200K mutation of the prion protein who presented with bilateral tonic–clonic seizures (BTCS) during long‐term video‐EEG monitoring. Semiologically, BTCS showed focal clinical signs such as head turning and eye deviation to the left. The ictal EEG started with generalized polyspikes. Interictal EEG showed generalized periodic discharges with right fronto‐temporal predominance (larger amplitude and earlier onset compared with other regions). MRI showed high‐intensity signals persistently in the right temporo‐parietal region on diffusion‐weighted images (DWI). Interictal single‐photon emission computed tomography (SPECT) showed hyperperfusion in the same region. Brain pathology revealed typical spongiform changes in CJD without other pathological findings of rapidly progressive dementia. Our case demonstrates that CJD can cause BTCS with generalized EEG changes and focal semiological/imaging abnormalities, suggesting that diffuse and inhomogeneous cortical and subcortical epileptic networks may develop in familial CJD.