Debate: When does a seizure imply epilepsy?

Epilepsy recently has been defined conceptually as a condition of at least one seizure, with an enduring predisposition to have seizures. It is not yet clear how to make this definition operational and practical. A diagnosis of epilepsy has potentially serious consequences for health, psychosocial well‐being, and economics, and, therefore, it should be made with a high level of certainty. A definite diagnosis of epilepsy can be made with two unprovoked seizures at least 24 h apart. This method has the benefit of simplicity and consistency with past epidemiologic studies. Nevertheless, certain circumstances suggest a high likelihood of having a second seizure, as evidenced by common clinical practice of considering treatment after a first unprovoked seizure in conjunction with additional risk factors (surrogate markers). One unifying approach is an operational definition of “definite epilepsy” after two unprovoked seizures at least 24 h apart. An operational definition of “probable epilepsy” can be established with one unprovoked seizure and clinical, electroencephalography (EEG), neuroimaging, genetic, or other information to suggest greater than a 50% chance of having another seizure. “Possible epilepsy” operationally would exist with a single unprovoked seizure and insufficient evidence to predict a high likelihood of recurrence. Future clinical and epidemiologic evidence would allow refinements of the operational definitions.

[1]  G. Holmes.  Benign Focal Epilepsies of Childhood , 1993, Epilepsia.

[2]  W. Hauser,et al.  Risk of seizure recurrence following a first unprovoked seizure in childhood: a prospective study. , 1990, Pediatrics.

[3]  J. Peltola,et al.  Outcome after prolonged convulsive seizures in 186 children: low morbidity, no mortality. , 2004, Developmental medicine and child neurology.

[4]  W. Hauser,et al.  Incidence of Acute Symptomatic Seizures in Rochester, Minnesota, 1935‐1984 , 1995, Epilepsia.

[5]  E. Perucca.  The treatment of the first seizure: The risks , 2008, Epilepsia.

[6]  S Shinnar,et al.  Predictors of multiple seizures in a cohort of children prospectively followed from the time of their first unprovoked seizure , 2000, Annals of neurology.

[7]  S. Peter.  Acarbose and Idiopathic Reactive Hypoglycemia , 2003, Hormone Research in Paediatrics.

[8]  C. Elger,et al.  Epileptic Seizures and Epilepsy: Definitions Proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) , 2005, Epilepsia.

[9]  W. Hauser,et al.  Seizure recurrence after a first unprovoked seizure. , 1982, The New England journal of medicine.

[10]  W. Hauser,et al.  A population-based study of seizures after traumatic brain injuries. , 1998, The New England journal of medicine.

[11]  Josemir W Sander,et al.  MEDICAL SCIENCE National General Practice Study of Epilepsy: newly diagnosed epileptic seizures in a general population , 1990, The Lancet.

[12]  S. Wiebe,et al.  An evidence‐based approach to the first seizure , 2008, Epilepsia.

[13]  S. Shinnar,et al.  Long-term prognosis of seizures with onset in childhood. , 1998, The New England journal of medicine.

[14]  W. Hauser,et al.  EEG and Other Early Predictors of Epilepsy Remission: A Community Study , 1988, Epilepsia.

[15]  M. Brodie,et al.  Diagnosing and predicting refractory epilepsy , 2005, Acta neurologica Scandinavica. Supplementum.

[16]  Prognosis.  Guidelines for Epidemiologic Studies on Epilepsy , 1993, Epilepsia.

[17]  Josemir W Sander,et al.  SUPPLEMENT - MANAGEMENT OF A FIRST SEIZURE The socioeconomic, cultural, and emotional implications of starting or withholding treatment in a patient with a first seizure , 2008 .

[18]  Olafur Kjartansson,et al.  Incidence of unprovoked seizures and epilepsy in Iceland and assessment of the epilepsy syndrome classification: a prospective study , 2005, The Lancet Neurology.

[19]  C. Panayiotopoulos,et al.  Juvenile Myoclonic Epilepsy: A 5‐Year Prospective Study , 1994, Epilepsia.

[20]  I. Leppik.  Epilepsy in the elderly: scope of the problem. , 2007, International review of neurobiology.

[21]  F. Barkhof,et al.  MRI criteria for dissemination in space in patients with clinically isolated syndromes: a multicentre follow-up study , 2006, The Lancet Neurology.

[22]  I. Leppik,et al.  Consensus statement on compliance in epilepsy. , 1988, Epilepsy research. Supplement.

[23]  L. Eberly,et al.  Antiepileptic drug use in nursing home admissions , 2003, Annals of neurology.

[24]  S. Moshé,et al.  Neuroimaging abnormalities in children with an apparent first unprovoked seizure , 2001, Epilepsy Research.

[25]  W. Hauser,et al.  Risk of recurrent seizures after two unprovoked seizures. , 1998, The New England journal of medicine.

[26]  S Shinnar,et al.  The risk of seizure recurrence after a first unprovoked afebrile seizure in childhood: an extended follow-up. , 1996, Pediatrics.

[27]  W. Hauser,et al.  Comment on Epileptic Seizures and Epilepsy: Definitions Proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) , 2005, Epilepsia.

[28]  M. Martín González,et al.  Seizure Recurrence After a First Unprovoked Seizure in Childhood: A Prospective Study , 2000, Epilepsia.

[29]  S. Shorvon,et al.  Early prognosis of epilepsy. , 1982, British medical journal.

[30]  J. Unterrainer,et al.  Long-term prognosis for childhood and juvenile absence epilepsy , 2004, Journal of Neurology.

[31]  D. Gilbert,et al.  Activate your online subscription , 2000, Neurology.

[32]  Anthony G Marson,et al.  Prediction of risk of seizure recurrence after a single seizure and early epilepsy: further results from the MESS trial , 2006, The Lancet Neurology.

[33]  C. Elger,et al.  Response: Definitions Proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) , 2005 .

[34]  D. Hirtz,et al.  Practice parameter: Treatment of the child with a first unprovoked seizure , 2003, Neurology.