Prospective study of epilepsy with generalized tonic–clonic seizures alone: Clinical features, response to treatment, and likelihood of medication withdrawal

Abstract

Abstract Objective This prospective study aimed to delineate the demographics, natural progression, and treatment response of patients newly diagnosed with epilepsy with generalized tonic–clonic seizures alone (EGTCA). Furthermore, our objective includes assessing the seizure recurrence rate post antiseizure medication (ASM) discontinuation within this cohort, alongside exploring predictive factors for seizure relapse. Methods The study cohort, derived from an ongoing, prospective, multicenter investigation on children and adults with new‐onset unprovoked seizures, included consecutive patients enrolled between March 2010 and March 2020, and meeting mandatory ILAE criteria for EGTCA diagnosis. Participants underwent a 3‐h sleep‐deprived video‐EEG recording along with an epilepsy protocol brain magnetic resonance imaging (MRI) with repeat EEG at each follow‐up. Cumulative time‐dependent probabilities of seizure recurrence were calculated using Kaplan–Meier survival analysis. Logistic regression identified variables associated with seizure recurrence following ASM taper. Results Eighty‐nine patients with a median age of 16 years were included, constituting 31% of those diagnosed with an idiopathic generalized epilepsy. Regarding the circadian distribution of seizures, 59.6% of patients exclusively experienced diurnal seizures, 12.4% exclusively nocturnal, and 28.1% experienced both diurnal and nocturnal seizures. Generalized spike–wave discharges (GSWD) were present in the initial EEG of 88% of patients. A GTC recurred in 14% of patients treated with ASM compared with 73% of untreated patients (p < 0.00001). ASM discontinuation was attempted in 50 patients after a median treatment duration of 3 years, with 44% experiencing a recurrence. Patient‐initiated taper and a mixed circadian seizure pattern independently predicted a higher likelihood of recurrence post‐ASM discontinuation. Significance Our findings underscore the importance of prompt treatment upon the diagnosis of EGTCA. Notably, lifelong treatment may not be imperative; patients seizure‐free for at least 2 years, with the absence of GSWD on EEG, often maintained seizure freedom after ASM withdrawal, especially with physician‐initiated tapering. Plain Language Summary Seizures in individuals diagnosed with “epilepsy with generalized tonic‐clonic seizures alone” (EGTCA) typically start during adolescence and often respond well to antiseizure medications. An electroencephalogram, which measure brain waves, will show abnormal discharges in most patients with EGTCA. Lifelong treatment with antiseizure medication is not necessary for everyone with EGTCA; approximately, 40% can successfully stop treatment without facing seizure recurrence. Patients who stop medication on their own have a higher risk of seizures returning compared with those who undergo cessation under a doctor's supervision.

Keywords

• antiseizure medication
• electroencephalography
• idiopathic generalized epilepsy
• prognostic factors
• recurrence rate
• withdrawal