New ILAE versus previous clinical status epilepticus semiologic classification: Analysis of a hospital-based cohort.

Abstract

In 2015, the International League Against Epilepsy (ILAE) issued a new status epilepticus (SE) classification, including a detailed semiologic axis. This study assesses frequencies of SE forms in a cohort of adult patients, and explores differences and practical implications as compared to a seizure-type-bound classification. The prospective adult SE registry of the Lausanne University Hospital (CHUV) was considered over 5 years (2011-2015); each SE episode was retrospectively reclassified for its semiology according to the new ILAE scheme. Mortality rates were retrieved for each subgroup of SE. Among 488 SE episodes, according to the seizure-type-bound classification, 230 (47%) had a generalized convulsive, and 29 (6%) had a nonconvulsive SE in coma; both categories overlapped almost perfectly between the two classifications. However, the 84 episodes with focal SE without consciousness impairment and the 141 episodes with consciousness impairment were each translated into two major (and five sub-) categories of the new ILAE classification, having markedly different mortality rates. In addition, of 140 episodes labeled as focal motor SE according to the new classification, 54% had concomitant consciousness impairment, whereas 46% did not; again, mortality rates were heterogeneous. Although generalized convulsive and nonconvulsive SE in coma show an almost perfect correspondence across SE semiologic classifications, focal SE is markedly heterogeneous and appears to be better reflected in the new classification, offering more clinically relevant subdivisions, also differing in mortality rates. This refined knowledge may allow the development of clinical prognostic scores that are more precise than existing tools, and should be taken into account for epidemiologic studies.