Focal Epileptogenic Lesions in Adult Patients with Epilepsy and Generalized Epileptiform Discharges

Abstract

Background and purpose: There are reports of successful resective epilepsy surgery for pediatric patients with epilepsy and generalized epileptiform discharges when they had focal epileptogenic lesions identified by MRI. However, there is limited information regarding adult patients with epilepsy who have both generalized epileptiform discharges and focal epileptogenic lesions.

Methods: To investigate the incidence and characteristics of adult patients who have both generalized epileptiform discharges and potentially epileptogenic lesions, we retrospectively analyzed data of clinical features and results of EEG and MRI of all patients with adult-onset epilepsy in a tertiary referral hospital.

Results: While 1315 patients were classified as having partial seizures, 207 patients were classified as having generalized seizures. Five of 207 patients (2.4%) with generalized seizures had potentially epileptogenic lesions. All the epileptogenic lesions were congenital or acquired during early life, such as focal cortical dysplasia, dysembryoplastic neuroepithelial tumor, and cerebromalacic change because of perinatal injury.

Conclusions: The presence of epileptogenic lesions in adult patients with generalized epileptiform discharges may be an incidental finding, but it has been suggested that some adult-onset epilepsy with generalized epileptiform discharges may actually have focal onset, which may have significant clinical implications for the choice of appropriate treatment.

Keywords: Focal seizure; Generalized epileptiform discharge; Secondary bilateral synchrony.

Figure 1

Illustrative cases. Patient No. 2: (A) MRI showing a left parasagittal frontal lesion and EEG showing a 4 Hz generalized spike and wave complex; (B) Patient No 4: MRI showing a left hippocampal lesion and EEG showing a 3 Hz generalized spike and wave complex.