Incidence of the different stages of status epilepticus in Eastern Finland: A population-based study

Abstract

Objective: The objective of this study was to determine the incidence in Eastern Finland of the different stages of status epilepticus (SE): 1) at the early stage of SE (a prolonged seizure lasting over 5 min);, 2) refractory SE (RSE), and 3) super-refractory SE (SRSE).

Methods: Firstly, we conducted a retrospective study on the incidence and outcome of intensive care unit (ICU)-treated RSE and SRSE in the adult population (≥16 years) in Kuopio University Hospital (KUH)'s special care responsibility area (840,000 inhabitants). Secondly, we conducted a prospective study using the International League Against Epilepsy (ILAE)'s new definition for SE (prolonged seizures lasting over 5 min), in adult (≥16 years) patients in the KUH municipality district (North Savo, 248,000 inhabitants).

Results: The retrospective study on ICU-treated RSE and SRSE from 2010 to 2012 identified 75 patients with RSE, of whom 21% were treated as SRSE, resulting in an annual age-adjusted incidence of ICU-treated RSE of 3.0/100,000 (95% confidence interval [CI]: 2.4-3.8) and 0.6/100,000 (95% CI: 0.4-1.0) for SRSE. In the prospective study of early stage SE (seizures lasting over 5 min), we identified 151 consecutive episodes during the 9-month study period in 2015, corresponding to an annual age-adjusted incidence of 81.1/100,000 (95% CI: 75.8-87.0). In this study, 11 seizure episodes became refractory, resulting in an age-adjusted incidence of RSE of 6.0/100,000 (95% CI: 3.4-10.4), of which seven were treated in the ICU [3.8/100,000 (95% CI: 1.8-7.8)], four were treated palliatively [2.2/100,000 (95% CI: 0.82-5.7)], and two evolved to SRSE [1.1/100,000 (95% CI: 0.3-4.3)].

Conclusions: The new ILAE 2015 definition of SE resulted in a four-fold increase in incidence of SE compared to the earlier 30-min definition reported earlier in Europe. In the epidemiology of RSE, the incidence of ICU-treated RSE, palliatively treated RSE, and SRSE needs to be separated. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures.

Keywords: Definition; Epidemiology; Epilepsy; Refractory; Seizures; Super-refractory.