Febrile seizure

Last reviewed: 6 Jun 2022
Last updated: 17 Jan 2019



History and exam

Key diagnostic factors

  • febrile illness
  • seizure
More key diagnostic factors

Other diagnostic factors

  • normal postictal exam
Other diagnostic factors

Risk factors

  • temperature elevation
  • young age
  • male sex
  • family history of febrile seizures
  • viral or bacterial infection outside the central nervous system
  • vaccinations
  • prenatal exposure to nicotine
  • iron deficiency
  • complications of pregnancy, labor, and delivery
More risk factors

Diagnostic investigations

1st investigations to order

  • diagnosis is clinical
More 1st investigations to order

Investigations to consider

  • lumbar puncture
  • viral studies
  • blood culture
  • EEG
  • brain MRI
  • serum sodium
  • CBC
  • serum glucose
  • iron studies
More investigations to consider

Treatment algorithm


febrile status epilepticus


first simple febrile seizure

first complex seizure


febrile illness with prior history of simple seizure or 1 complex seizure

history of 2 or more complex febrile seizures with ineffective diazepam treatment



Leena Mewasingh, MBChB, MSc

Consultant Paediatric Neurologist

St Mary’s Hospital

Imperial College Healthcare NHS Trust




LM has received funding from drug companies (e.g., Eisai) to attend medical conferences and been invited to an educational symposium (Novartis, LivaNova).

Frances Morrison, MBChB, DCH, MRCPCH

Paediatric Specialist Trainee

St Mary’s Hospital

Imperial College Healthcare NHS Trust




FM declares that she has no competing interests.


Dr Leena Mewasingh and Dr Frances Morrison wish to gratefully acknowledge Dr John J. Millichap and Dr J. Gordon Millichap, previous contributors to this topic. JJM serves as an Associate Editor of Neurology and serves on the editorial board of Pediatric Neurology Briefs; volunteers on the medical advisory board of The Jack Pribaz Foundation (KCNQ2.org); received speaker honoraria from Invitae; received royalties for online monographs from Up-To-Date; served on the scientific advisory board for Mallinckrodt; is principal investigator for a clinical trial funded by UCB Pharma; and is the principal investigator for research grants from Citizens United for Research in Epilepsy and the Thrasher Research Fund. JJM is an author of a number of references cited in this topic. JGM is an author of a number of references cited in this topic.

Peer reviewers

Robert S. Rust, Jr., MA, MD


Department of Neurology

University of Virginia Health System




RSR declares that he has no competing interests.

  • Differentials

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  • Guidelines

    • Summary of recommendations for the management of infantile seizures: task force report for the ILAE Commission of Pediatrics
    • ACR appropriateness criteria: seizures - child
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  • Patient leaflets

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