First seizure and seizure mimics

The organising idea of this topic is that the child after a first event is managed along three questions, in order: was it a seizure, what type and cause, and does it need a drug today. The first question is the one candidates most often skip, and it is the one that does the most harm when answered wrongly — because labelling a non-epileptic event as epilepsy exposes a child to unnecessary investigations, driving restrictions, stigma, and the cognitive and teratogenic burden of antiseizure medication. [9] [10]

This page covers the ILAE definition of epilepsy and its 2017 classification of seizure types, the recurrence risk after a first unprovoked seizure, the seizure-versus-mimic decision at the bedside, the tiered investigation strategy, the resuscitation of status epilepticus, and the shared decision about starting treatment. It links to the epilepsy syndromes, febrile seizures, syncope and status epilepticus leaves for the syndromic, febrile, cardiovascular and emergency-management depth that each demands. [1] [7]

Overview & Definition

A seizure is the transient occurrence of signs or symptoms produced by abnormal excessive or synchronous neuronal activity in the brain. The clinician at the bedside rarely sees the seizure itself — the event is usually over by the time the child arrives — so the diagnosis rests almost entirely on the account of a witness, ideally supplemented by a home video. [9] A provoked seizure is one driven by a transient systemic or metabolic insult such as fever, electrolyte disturbance, hypoglycaemia, head trauma, drug withdrawal or central nervous system infection; an unprovoked seizure occurs in the absence of such a trigger, and it is the unprovoked event that opens the epilepsy pathway. [4]

Epilepsy, by the 2014 ILAE practical definition, is a disease of the brain defined by any one of three conditions: two or more unprovoked seizures occurring more than twenty-four hours apart; a single unprovoked seizure with a recurrence risk of at least sixty per cent over the next ten years; or a recognised epilepsy syndrome. [2] The clinical consequence is that a single unprovoked seizure is not, by itself, epilepsy — the threshold for the diagnosis is high, deliberately, to protect children from a label that carries driving, occupational, insurance and psychosocial weight.

The practical corollary is that the first consultation after a possible seizure has two diagnostic aims. The first is to decide whether the event was epileptic; the second, only if it was, is to classify it and search for a cause. Jumping to the cause before settling the nature of the event is the single most common reason that a child is started on an antiseizure drug for a mimic. [9]

References12Show ledgerHide ledger

1. [1]Fisher RS; Cross JH; French JA; et al Operational classification of seizure types by the International League Against Epilepsy: Position Paper of the ILAE Commission for Classification and Terminology Epilepsia, 2017.PMID 28276060
2. [2]Fisher RS; Acevedo C; Arzimanoglou A; et al ILAE official report: a practical clinical definition of epilepsy Epilepsia, 2014.PMID 24730690
3. [3]Trinka E; Cock H; Hesdorffer D; et al A definition and classification of status epilepticus--Report of the ILAE Task Force on Classification of Status Epilepticus Epilepsia, 2015.PMID 26336950
4. [4]Hirtz D; Ashwal S; Berg A; et al Practice parameter: evaluating a first nonfebrile seizure in children: report of the quality standards subcommittee of the American Academy of Neurology, The Child Neurology Society, and The American Epilepsy Society Neurology, 2000.PMID 10980722
5. [5]Hirtz D; Berg A; Bettis D; et al Practice parameter: treatment of the child with a first unprovoked seizure: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society Neurology, 2003.PMID 12552027
6. [6]Baldin E; Hauser WA; Buchhalter JR; et al Yield of epileptiform electroencephalogram abnormalities in incident unprovoked seizures: a population-based study Epilepsia, 2014.PMID 25041095
7. [7]Haut SR; Shinnar S Considerations in the treatment of a first unprovoked seizure Semin Neurol, 2008.PMID 18777475
8. [8]Subcommittee on Febrile Seizures Neurodiagnostic evaluation of the child with a simple febrile seizure Pediatrics, 2011.PMID 21285335
9. [9]Leibetseder A; Eisermann M; LaFrance WC Jr; et al How to distinguish seizures from non-epileptic manifestations Epileptic Disord, 2020.PMID 33399092
10. [10]Doss J Psychogenic non-epileptic seizures in youth: Individual and family psychiatric characteristics Front Psychiatry, 2022.PMID 36590633
11. [11]Dalziel SR; Borland ML; Furyk J; et al Levetiracetam versus phenytoin for second-line treatment of convulsive status epilepticus in children (ConSEPT): an open-label, multicentre, randomised controlled trial Lancet, 2019.PMID 31005386
12. [12]Berg AT; Shinnar S Complex febrile seizures Epilepsia, 1996.PMID 8635422