Febrile seizure

Last reviewed: 7 Jan 2023
Last updated: 19 Jul 2022



History and exam

Key diagnostic factors

  • presence of risk 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
  • antenatal exposure to nicotine
  • iron deficiency
  • complications of pregnancy, labour, 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
  • FBC
  • capillary blood gluscose
  • 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



Damian Roland, BMedSci, MBBS, FRCPCH, PhD

Honorary Associate Professor and Consultant in Paediatric Emergency Medicine

Paediatric Emergency Medicine Leicester Academic (PEMLA) Group

Children’s Emergency Department

Leicester Royal Infirmary




DR declares that he is a previous member of the National Institute for Health and Care Excellence Feverish Illness in Children Guideline Group.


Dr Damian Roland would like to gratefully acknowledge Dr Leena Mewasingh, Dr Frances Morrison, Dr John J. Millichap and Dr J. Gordon Millichap, previous contributors to this topic. LM has received funding from drug companies (e.g., Eisai) to attend medical conferences and been invited to an educational symposium (Novartis, LivaNova). FM declares that she has no competing interests. 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.

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