We present a case of idiopathic generalized epilepsy (IGE) with seizures manifesting in the context of Graves disease and unusual interictal EEG pattern of bilateral independent 3 Hz spike and wave activity.
A 33-year old man with three generalized tonic-clonic seizures (GTCS) in history admitted for overnight video-EEG. At the age of 28, he had his first seizure soon after being diagnosed with Graves’ disease. For four years, he received thiamazole and then underwent total thyroidectomy. EEG showed a high number of generalized 3-Hz spike-and-wave discharges (GSWD) but also revealed numerous runs of bitemporal independent lateralized 3-Hz spike-and-wave activity (LSWA). GSWD and LSWA were mostly independent and had slightly different morphology. A diagnosis of IGE with GTCS upon awakening was made. On levetiracetam therapy, the patient demonstrated no seizure recurrence during 2-year follow-up. Repeated overnight EEG showed significant GSWD reduction and complete LSWA suppression.
To our knowledge, in patients with IGE, strictly lateralized spike-and-wave activity was never reported. In this case, thyroid dysfunction seemed to increase propensity to generate spontaneous seizures. We speculate that thyroid dysfunction superimposed on IGE thalamocortical network oscillations resulted in uncommon bitemporal independent LSWA.

© 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V.