Incidence of SUDEP in a cohort of patients with refractory epilepsy: the role of surgery and lesion localization

Abstract

The aim of this study was to verify incidence and characteristics of sudden unexpected death in patients (SUDEP) with refractory epilepsy and its relation to previous surgery and lesion localization. A cross sectional study was carried out in a cohort of 550 patients with refractory epilepsy followed up by the Epilepsy Surgery Program of the University Hospital of PUCRS, Porto Alegre, Brazil, between January, 1992 and July, 2002. Patients were allocated in two groups (operated and non operated). Seizure type, distribution of interictal spikes and MRI findings were correlated with the SUDEP outcome. The estimated incidence of probable SUDEP amounted to 29:1000 individuals. Probable SUDEP occurred in 1.2% of the 166 patients of the non operated group and in 3.7% of the 384 patients who were operated (OR=3.02, 95% CI 0.69-13.16) (p=0.11). Comparing patients who died to patients alive in the operated group a significant difference was observed concerning the following variables: SUDEP patients had a predominance of generalized seizures (p=0.002), extratemporal lesion on MRI (p<0.001) and epileptiform activity over extratemporal regions (p=0.001). In surgically treated patients with refractory epilepsy, an extratemporal location of the lesion and of the epileptiform discharges significantly correlated to SUDEP. Thus it is possible that in those patients; the underlying disease may play a role in the pathogenesis of SUDEP.