Febrile seizure

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Febrile seizure
ICD-10 R56.0
ICD-9 780.31
OMIM 604352
DiseasesDB 4777
MedlinePlus 000980
eMedicine neuro/134
MeSH D003294

A febrile seizure, also known as a fever fit or febrile convulsion, is a convulsion associated with a significant rise in body temperature. They most commonly occur in children between the ages of 6 months and 5 years of age.[1] They are more common in boys than girls.[2]

Signs and symptoms[edit]

During generalized febrile seizures, the body will become stiff and the arms and legs will begin twitching. The child loses consciousness, although their eyes remain open. Breathing can be irregular. They may become incontinent (wet or soil themselves); they may also vomit or have increased secretions (foam at the mouth). The seizure normally lasts for less than five minutes.[3]


Genetic associations[4]
Type OMIM Gene
FEB3A 604403 SCN1A
FEB3B 604403 SCN9A
FEB4 604352 GPR98
FEB8 611277 GABRG2

Febrile seizures are due to fevers,[2] usually those greater than 38 °C (100.4 °F).[5] The cause of the fevers is often a viral illness.[1] The likelihood of a febrile seizure is related to how high the temperature reaches.[1] Some feel that the rate of increase is not important[1] while others feel the rate of increase is a risk factor.[6] This latter position has not been proven.[6]

The seizures occur, by definition, without an intracranial infection or metabolic problems.[1] They run in families.[1] Several genetic associations have been identified.[4]


The diagnosis is arrived at by eliminating more serious causes of seizure and fever: in particular, meningitis and encephalitis. However, in locales in which children are immunized for pneumococcal and Haemophilus influenzae, the prevalence of bacterial meningitis is low. If a child has recovered and is acting normally, bacterial meningitis is very unlikely.

Blood test, imaging of the brain and an electroencephalogram are generally not needed.[1]


There are three types of febrile seizures.

  • A simple febrile seizure is characterized by shorter duration (lasting less than 15 minutes), no focal features (meaning the shaking is general rather than restricted to a part of the body such as an arm or leg), and if they do occur in series, the total duration is less than 30 minutes (classically a generalized tonic-clonic seizure).
  • A generalized febrile seizure also known as a complex febrile seizure is one in which the seizure lasts longer than 15 minutes or multiple episodes occur within 24 hours and generally does have focal features.
  • A febrile status epilepticus is a febrile seizure that lasts for longer than 30 minutes. It can occur in up to 5% of febrile seizure cases.[7]


In those with a history of febrile seizures medications (both antipyretics and anticonvulsants) have not been found effective for prevention; however, some appear to be associated with harm.[8] They are thus not recommended as an effort to prevent further seizures.[1]


The vast majority of people do not require treatment for either their acute presentation or for recurrences.[citation needed] In those who have prolonged seizures intravenous lorazepam is recommended.[1] The other benzodiazepines, midazolam and diazepam are also reasonable options.


Long term outcomes are generally good with little risk of neurological problems or epilepsy.[1] Those who have one febrile seizure have an approximately 40% chance of having another one in the next two years, with the risk being greater in those who are younger.[1]

Simple febrile seizures do not tend to recur frequently (children tend to outgrow them); and do not make the development of adult epilepsy significantly more likely (about 3–5%), compared with the general public (1%).[9] Children with febrile convulsions are more likely to have a febrile seizure in the future if they were young at their first seizure (less than 18 months old), a family history of a febrile convulsions in first-degree relatives (a parent or sibling), have a short time between the onset of fever and the seizure, had a low degree of fever before their seizure, or a seizure history of abnormal neurological signs or developmental delay.[citation needed] Similarly, the prognosis after a complex febrile seizure is excellent, although an increased risk of death has been shown for complex febrile seizures, partly related to underlying conditions.[10]


Febrile seizures happen between the ages of six months and five years in 2-5% of children.[1]


  1. ^ a b c d e f g h i j k l Graves, RC with Oehler, K and Tingle, LE (Jan 15, 2012). "Febrile seizures: risks, evaluation, and prognosis". American family physician 85 (2): 149–53. PMID 22335215. 
  2. ^ a b Ronald M. Perkin, ed. (2008). Pediatric hospital medicine : textbook of inpatient management (2nd ed. ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 266. ISBN 9780781770323. 
  3. ^ http://www.nhs.uk/Conditions/Febrile-convulsions/Pages/Symptoms.aspx
  4. ^ a b Nakayama J, Arinami T (August 2006). "Molecular genetics of febrile seizures". Epilepsy Res. 70 Suppl 1: S190–8. doi:10.1016/j.eplepsyres.2005.11.023. PMID 16887333. 
  5. ^ Simon, David A. Greenberg, Michael J. Aminoff, Roger P. (2012). "12". Clinical neurology (8th ed. ed.). New York: McGraw-Hill Medical. ISBN 978-0071759052. 
  6. ^ a b Engel, Jerome (2008). Epilepsy : a comprehensive textbook (2nd ed. ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 661. ISBN 9780781757775. 
  7. ^ Ahmad, S; Marsh, ED (September 2010). "Febrile status epilepticus: current state of clinical and basic research.". Semin Pediatr Neurol. 17 (3). doi:10.1016/j.spen.2010.06.004. PMID 20727483. Retrieved 2013-12-23. 
  8. ^ Offringa, M; Newton, R (Apr 18, 2012). "Prophylactic drug management for febrile seizures in children". The Cochrane database of systematic reviews 4: CD003031. doi:10.1002/14651858.CD003031.pub2. PMID 22513908. 
  9. ^ Shinnar, S; Glauser, TA (January 2002). "Febrile seizures". Journal of child neurology. 17 Suppl 1: S44–52. doi:10.1177/08830738020170010601. PMID 11918463. 
  10. ^ Vestergaard M, Pedersen MG, Ostergaard JR, Pedersen CB, Olsen J, Christensen J (August 2008). "Death in children with febrile seizures: a population-based cohort study". Lancet 372 (9637): 457–63. doi:10.1016/S0140-6736(08)61198-8. PMID 18692714.