Idiopathic generalized epilepsy: Phenotypic and electroencephalographic observations in a large cohort from South India

Abstract

Purpose: We studied the phenotype and electroencephalographic (EEG) features, and therapeutic aspects of idiopathic generalized epilepsies (IGEs) in South Indian population.

Patients and methods: This prospective cross-sectional hospital-based study was carried out on non-consecutive 287 patients (age 22.2 ± 7.7 years; M:F = 139:148) with IGE syndrome. Their clinical and EEG observations were analyzed.

Results: Majority of the patients had onset of seizures <20 years of age (n = 178; 62%). Thirty one patients (10.8%) had family history of epilepsy. Nearly half of them (49.9%) had <5 years of duration of seizures. The type of IGEs included Juvenile myoclonic epilepsy (JME): 115 (40.1%); IGE with generalized tonic-clonic seizures (GTCS) only: 102 (39.02%); childhood absence epilepsy (CAE): 35 (12.2%); GTCS on awakening: 15 (5.2%); Juvenile absence epilepsy (JAE): 11 (3.8%); and unclassified seizures: 9 (3.1%). The triggering factors noted in 45% were sleep deprivation (20%), non-compliance and stress in 5% each. The EEG (n = 280) showed epileptiform discharges in about 50% of patients. Epileptiform discharges during activation was observed in 40/249 patients (16.1%): Hyperventilation in 32 (12.8%) and photic stimulation in 19 (7.6%). The seizures were well controlled with anti-epileptic drugs (AEDs) in 232 (80.8%) patients and among them, 225 (78.4%) patients were on monotherapy. Valproate (n = 131) was the most frequently prescribed as monotherapy.

Conclusions: This is one of the largest cohort of patients with IGE. This study reiterates the importance of segregating IGE syndrome and such analysis will aid to the current understanding and management.

Keywords: Electroencephalographic; epilepsy syndromes; idiopathic generalized epilepsy; seizure types.

Figure 1

Mrs. K aged 25 years with uncontrolled seizures since 19 years of age on tablet phenobarbitone 60 mg/day. Initial EEG shows generalized bursts of high amplitude spikes and slow waves in (a) spontaneous record, (b) hyperventilation, (c) post-hyperventilation, (d) photic stimulation, (e) during eye closure; and (f) repeat EEG after 1 week of valproic acid therapy showed no epileptiform activity