Clinical Review

First seizures in adults

BMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2470 (Published 15 April 2014) Cite this as: BMJ 2014;348:g2470

This article has a correction. Please see:

  1. Heather Angus-Leppan, consultant neurologist and epilepsy lead1, honorary senior lecturer2
  1. 1Clinical Neurosciences, Royal Free London NHS Foundation Trust and Barnet Chase Farm Hospitals NHS Trust, London, UK
  2. 2Institute of Neurology, University College London and Centre for Restorative Neuroscience, Imperial College London
  1. Correspondence to: H Angus-Leppan, Royal Free Hospital, Pond Street, London NW3 2QG heather.angus-leppan{at}nhs.net
  • Accepted 25 March 2014

Summary points

  • First seizures range from a brief subjective experience (aura) to a major tonic-clonic seizure

  • Up to 10% of people living to 80 years of age have one or more seizures; half of these are febrile convulsions

  • In 85% of patients, the diagnosis comes from the history; blood tests, electrocardiography, electroencephalography, and sometimes magnetic resonance imaging are important for classification and risk prediction

  • 50% of patients with an apparent “first seizure” have had other minor seizures, so their diagnosis is epilepsy

  • Low risk patients with first seizures have no neurological deficits, normal magnetic resonance imaging and electroencephalography, and a 35% risk of recurrence at five years; they are not usually offered treatment

  • High risk patients with first seizures have neurological deficit, magnetic resonance imaging and/or electroencephalography abnormalities, and a 70% risk of recurrence at five years; they are offered treatment

A seizure is a clinical manifestation of presumed or proved abnormal electrical activity in the brain. A first seizure can range from a fleeting subjective experience such as déjà vu or a twitch (myoclonic jerk) through to a tonic-clonic convulsion. Some seizure manifestations overlap with normal phenomena. A single seizure may be provoked (with an acute precipitant that may or may not recur) or unprovoked (idiopathic or of unknown cause). Epilepsy is defined as more than one seizure.

Sources and selection criteria

I consulted my personal archive of references and searched Medline and the Cochrane Collaboration and Clinical Evidence databases, using “seizure”, “first seizure”, and specific topics. I also consulted the National Institute for Health and Care Excellence’s guidelines. I carefully examined randomised controlled trials, systematic reviews, and meta-analyses. Ranges of results are used in preference to averages, because pooling results from methodologically diverse studies is not accurate

This article focuses on the diagnosis of first seizures and differentiation from their “mimics” in adults. The …

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