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Epilepsia. 2015 Oct;56(10):1515-23. doi: 10.1111/epi.13121. Epub 2015 Sep 4.

A definition and classification of status epilepticus--Report of the ILAE Task Force on Classification of Status Epilepticus.

Author information

1
Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
2
Center for Cognitive Neuroscience, Salzburg, Austria.
3
Department of Public Health Technology Assessment, UMIT - University for Health Sciences, Medical Informatics and Technology, Hall.i.T., Austria.
4
Institute of Medical & Biomedical Education, Epilepsy Group, Atkinson Morley Regional Neuroscience Centre, St. Georges University Hospitals NHS Foundation Trust, St George's University of London, London, United Kingdom.
5
GH Sergievsky Center and Department of Epidemiology, Columbia University, New York, New York, U.S.A.
6
Department of Clinical Neurosciences, CHUV and University of Lausanne, Lausanne, Switzerland.
7
Florey Institute of Neuroscience and Mental Health, Austin Health and Royal Children's Hospital, University of Melbourne, Melbourne, Victoria, Australia.
8
Departments of Neurology, Pediatrics, and Epidemiology and Population Health Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, U.S.A.
9
National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, London, United Kingdom.
10
Department of Neurology, University of California, San Francisco, California, U.S.A.

Abstract

The Commission on Classification and Terminology and the Commission on Epidemiology of the International League Against Epilepsy (ILAE) have charged a Task Force to revise concepts, definition, and classification of status epilepticus (SE). The proposed new definition of SE is as follows: Status epilepticus is a condition resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms, which lead to abnormally, prolonged seizures (after time point t1 ). It is a condition, which can have long-term consequences (after time point t2 ), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures. This definition is conceptual, with two operational dimensions: the first is the length of the seizure and the time point (t1 ) beyond which the seizure should be regarded as "continuous seizure activity." The second time point (t2 ) is the time of ongoing seizure activity after which there is a risk of long-term consequences. In the case of convulsive (tonic-clonic) SE, both time points (t1 at 5 min and t2 at 30 min) are based on animal experiments and clinical research. This evidence is incomplete, and there is furthermore considerable variation, so these time points should be considered as the best estimates currently available. Data are not yet available for other forms of SE, but as knowledge and understanding increase, time points can be defined for specific forms of SE based on scientific evidence and incorporated into the definition, without changing the underlying concepts. A new diagnostic classification system of SE is proposed, which will provide a framework for clinical diagnosis, investigation, and therapeutic approaches for each patient. There are four axes: (1) semiology; (2) etiology; (3) electroencephalography (EEG) correlates; and (4) age. Axis 1 (semiology) lists different forms of SE divided into those with prominent motor systems, those without prominent motor systems, and currently indeterminate conditions (such as acute confusional states with epileptiform EEG patterns). Axis 2 (etiology) is divided into subcategories of known and unknown causes. Axis 3 (EEG correlates) adopts the latest recommendations by consensus panels to use the following descriptors for the EEG: name of pattern, morphology, location, time-related features, modulation, and effect of intervention. Finally, axis 4 divides age groups into neonatal, infancy, childhood, adolescent and adulthood, and elderly.

KEYWORDS:

Classification; Definition; Seizure; Seizure duration; Status epilepticus

PMID:
26336950
DOI:
10.1111/epi.13121
[Indexed for MEDLINE]
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