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Febrile seizures

Description

There is a 2-5% risk of febrile seizures in normal children. [Baumann: 2000] Characteristics of a simple febrile seizure include: [American: 1996]
  • Seizure occurs in a child who is normally developing, without underlying neurologic problems, evidence of meningitis or encephalitis, or metabolic disturbances;
  • Child is 6 months to 5 years of age;
  • Fever is present before the seizure;
  • The seizure is generalized, involving arms and legs;
  • Only one seizure in 24 hours;
  • Seizure lasting less than 15 min.
  • Children with complex febrile seizures have a different prognosis and treatment than those with simple febrile seizures. If the seizure has any of the following features, it is a complex febrile seizure:
    • focal features
    • prolonged (greater than 15 min)
    • recurring within 24 hours of a first febrile seizure
    • occurring in a child with a history of afebrile seizures
    • occurring in a child with a prior neurological insult
    • occurring in a child with an abnormal baseline neurologic exam

Diagnosis

In the clinical setting of a simple febrile seizure, i.e. in a child with the appropriate history and normal exam, brain imaging, blood studies (CBC, lytes, calcium, phosphorus, magnesium, glucose) and EEG are not thought to be necessary in children over a year of age. The AAP recommends that an LP be strongly considered in childen under 12 months, in children that have any sign of intracranial infection such as neck stiffness or Kernig and Brudzinski signs, and in children that might have been pre-treated with antibiotics. They recommend that an LP be considered in children from 12 to 18 months as meningeal signs might be difficult to appreciate in this age group. [American: 1999]

Treatment

Treatment of the fever by acetaminophen or ibuprofen does not prevent the reoccurrence of febrile seizures, however oral diazepam (0.33 mg/kg every 8 hours at the beginning of a febrile illness) has been shown to be helpful. [Pavlidou: 2006] Although a continuous course of antiepileptic medications might be effective in decreasing febrile seizure recurrence, febrile seizures do not warrant the potential toxicities of these medications. Treatment doesn't appear to improve long term outcome in febrile seizures and outcome is good without medical intervention.

In children with prolonged frequent febrile seizures, a prescription for rectal diazepam or nasal midazolam is sometimes given for home use.

See [Steering: 2008] and [Subcommittee: 2011].

Prognosis

Simple febrile seizures are benign and have an excellent prognosis; the child is unlikely to have developmental problems or future epilepsy. Treatment does not appear to improve long term outcomes and good outcomes are expected.

The risk of epilepsy for all children is 1%; having febrile seizures increases this either not at all or only minimally to 2.4% [Annegers: 1987] or 6% [Vestergaard: 2007]. Children who are younger than 12 months, or have a family history of epilepsy appear to be in the higher risk range.

Recurrence risk for future febrile seizures is 50% for children under one year of age, 30% for children over one year, and 50% for children who have experienced two febrile seizures (not given by age range).

There is some question of an association between mesial temporal sclerosis and complex febrile seizures but this association if it exists, is not understood. There may be an underlying genetic predisposition to either or both. [Ng: 2006] [Cendes: 2004] [Tarkka: 2003]

Resources

Practice Guidelines

Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures.
Febrile seizures: Clinical practice guideline for the long-term management of the child with simple febrile seizures.
Pediatrics. 2008;121(6):1281-1286. / Full Text
Treatment guidelines for the typically developing child with simple febrile seizures

Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures American Academy of Pediatrics.
Febrile seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures.
Pediatrics. 2008;121(6):1281-6. PubMed abstract

Subcommittee on febrile seizures.
Neurodiagnostic evaluation of the child with a simple febrile seizure.
Pediatrics. 2011;127(2):389-94. PubMed abstract

Helpful Articles

PubMed search for articles on Febrile Seizures in children for the last 3 years.

Capovilla G, Mastrangelo M, Romeo A, Vigevano F.
Recommendations for the management of "febrile seizures": Ad Hoc Task Force of LICE Guidelines Commission.
Epilepsia. 2009;50 Suppl 1:2-6. PubMed abstract

Mohebbi MR, Holden KR, Butler IJ.
FIRST: a practical approach to the causes and management of febrile seizures.
J Child Neurol. 2008;23(12):1484-8. PubMed abstract

Authors

Compiled and edited by: Lynne M Kerr, MD, PhD - 4/2013

Page Bibliography

American Academy of Pediatrics, Committee on Quality Improvement, Subcommittee on Febrile Seizures.
Practice parameter: long-term treatment of the child with simple febrile seizures.
Pediatrics. 1999;103(6):1307-1309. PubMed abstract / Full Text
The complete practice parameter can be found on the American Academy of Pediatrics site by clicking the "Full Text" link above.

American Academy of Pediatrics, Provisional Committee on Quality Improvement, Subcommittee on Febrile Seizures.
Practice parameter: the neurodiagnostic evaluation of the child with a first simple febrile seizure.
Pediatrics. 1996;97(5):769-72. PubMed abstract
The complete practice parameter, along with a graphic algorithm of the recommended evaluation, can be found on the American Academy of Pediatrics site by clicking the "Full Text" link above.

Annegers JF, Hauser WA, Shirts SB, Kurland LT.
Factors prognostic of unprovoked seizures after febrile convulsions.
N Engl J Med. 1987;316(9):493-8. PubMed abstract

Baumann RJ, Duffner PK.
Treatment of children with simple febrile seizures: the AAP practice parameter. American Academy of Pediatrics.
Pediatr Neurol. 2000;23(1):11-7. PubMed abstract

Cendes F.
Febrile seizures and mesial temporal sclerosis.
Curr Opin Neurol. 2004;17(2):161-4. PubMed abstract

Ng YT, McGregor AL, Duane DC, Jahnke HK, Bird CR, Wheless JW.
Childhood mesial temporal sclerosis.
J Child Neurol. 2006;21(6):512-7. PubMed abstract

Pavlidou E, Tzitiridou M, Panteliadis C.
Effectiveness of intermittent diazepam prophylaxis in febrile seizures: long-term prospective controlled study.
J Child Neurol. 2006;21(12):1036-40. PubMed abstract

Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures American Academy of Pediatrics.
Febrile seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures.
Pediatrics. 2008;121(6):1281-6. PubMed abstract

Subcommittee on febrile seizures.
Neurodiagnostic evaluation of the child with a simple febrile seizure.
Pediatrics. 2011;127(2):389-94. PubMed abstract

Tarkka R, Paakko E, Pyhtinen J, Uhari M, Rantala H.
Febrile seizures and mesial temporal sclerosis: No association in a long-term follow-up study.
Neurology. 2003;60(2):215-8. PubMed abstract

Vestergaard M, Pedersen CB, Sidenius P, Olsen J, Christensen J.
The Long-Term Risk of Epilepsy after Febrile Seizures in Susceptible Subgroups.
Am J Epidemiol. 2007. PubMed abstract