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Pediatric Febrile Seizures

  • Author: Robert J Baumann, MD; Chief Editor: Amy Kao, MD  more...
 
Updated: Oct 14, 2015
 

Practice Essentials

Pediatric febrile seizures, which represent the most common childhood seizure disorder, exist only in association with an elevated temperature. Evidence suggests, however, that they have little connection with cognitive function, so the prognosis for normal neurologic function is excellent in children with febrile seizures.[1]

Epidemiologic studies have led to the division of febrile seizures into 3 groups, as follows:

  • Simple febrile seizures
  • Complex febrile seizures
  • Symptomatic febrile seizures

Essential update: Starting MMR/MMRV vaccination earlier may reduce seizure risk

In a case-series analysis of a cohort of 323,247 US children born from 2004 to 2008, Hambidge et al found that delaying the first dose of measles-mumps-rubella (MMR) or measles-mumps-rubella-varicella (MMRV) vaccine beyond the age of 15 months may more than double the risk of postvaccination seizures in the second year of life.[2, 3]

In infants, there was no association between vaccination timing and postvaccination seizures.[3] In the second year of life, however, the incident rate ratio (IRR) for seizures within 7-10 days was 2.65 (95% confidence interval [CI], 1.99-3.55) after first MMR doses at 12-15 months of age, compared with 6.53 (95% CI, 3.15-13.53) after first MMR doses at 16-23 months. For the MMRV vaccine, the IRR for seizures was 4.95 (95% CI, 3.68-6.66) after first doses at 12-15 months, compared with 9.80 (95% CI, 4.35-22.06) for first doses at 16-23 months.

Signs and symptoms

Simple febrile seizure

  • The setting is fever in a child aged 6 months to 5 years
  • The single seizure is generalized and lasts less than 15 minutes
  • The child is otherwise neurologically healthy and without neurologic abnormality by examination or by developmental history
  • Fever (and seizure) is not caused by meningitis, encephalitis, or any other illness affecting the brain
  • The seizure is described as either a generalized clonic or a generalized tonic-clonic seizure

Complex febrile seizure

  • Age, neurologic status before the illness, and fever are the same as for simple febrile seizure
  • This seizure is either focal or prolonged (ie, >15 min), or multiple seizures occur in close succession

Symptomatic febrile seizure

  • Age and fever are the same as for simple febrile seizure
  • The child has a preexisting neurologic abnormality or acute illness

See Clinical Presentation for more detail.

Diagnosis

No specific laboratory studies are indicated for a simple febrile seizure. Physicians should instead focus on diagnosing the cause of fever. Other laboratory tests may be indicated by the nature of the underlying febrile illness. For example, a child with severe diarrhea may benefit from blood studies for electrolytes.

With regard to lumbar puncture, the following should be kept in mind:

  • Strongly consider lumbar puncture in children younger than 12 months, because the signs and symptoms of bacterial meningitis may be minimal or absent in this age group
  • Lumbar puncture should be considered in children aged 12-18 months, because clinical signs and symptoms of bacterial meningitis may be subtle in this age group
  • In children older than 18 months, the decision to perform lumbar puncture rests on the clinical suspicion of meningitis

See Workup for more detail.

Management

On the basis of risk/benefit analysis, neither long-term nor intermittent anticonvulsant therapy is indicated for children who have experienced 1 or more simple febrile seizures.

If, however, preventing subsequent febrile seizures is essential, oral diazepam would be the treatment of choice. It can reduce the risk of febrile seizure recurrence and, because it is intermittent, probably has the fewest adverse effects.[4]

See Treatment and Medication for more detail.

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Background

Febrile seizures are the most common seizure disorder in childhood. Since early in the 20th century, people have debated about whether these children would benefit from daily anticonvulsant therapy. Epidemiologic studies have led to the division of febrile seizures into 3 groups, as follows: simple febrile seizures, complex febrile seizures, and symptomatic febrile seizures.

Simple febrile seizure

See the list below:

  • The setting is fever in a child aged 6 months to 5 years.
  • The single seizure is generalized and lasts less than 15 minutes.
  • The child is otherwise neurologically healthy and without neurological abnormality by examination or by developmental history.
  • Fever (and seizure) is not caused by meningitis, encephalitis, or other illness affecting the brain.

Complex febrile seizure

See the list below:

  • Age, neurological status before the illness, and fever are the same as for simple febrile seizure.
  • This seizure is either focal or prolonged (ie, >15 min), or multiple seizures occur in close succession.

Symptomatic febrile seizure

See the list below:

  • Age and fever are the same as for simple febrile seizure.
  • The child has a preexisting neurological abnormality or acute illness.
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Pathophysiology

This is a unique form of epilepsy that occurs in early childhood and only in association with an elevation of temperature. The underlying pathophysiology is unknown, but genetic predisposition clearly contributes to the occurrence of this disorder.[5]

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Frequency

United States

Febrile seizures occur in 2-5% of children aged 6 months to 5 years in industrialized countries. Among children with febrile seizures, about 70-75% have only simple febrile seizures, another 20-25% have complex febrile seizures, and about 5% have symptomatic febrile seizures.

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Mortality/Morbidity

See the list below:

  • Children with a previous simple febrile seizure are at increased risk of recurrent febrile seizures; this occurs in approximately one third of cases.
  • Children younger than 12 months at the time of their first simple febrile seizure have a 50% probability of having a second seizure. After 12 months, the probability decreases to 30%.
  • Children who have simple febrile seizures are at an increased risk for epilepsy. The rate of epilepsy by age 25 years is approximately 2.4%, which is about twice the risk in the general population.
  • The literature does not support the hypothesis that simple febrile seizures lower intelligence (ie, cause a learning disability) or are associated with increased mortality [6] .

Sex

Males have a slightly (but definite) higher incidence of febrile seizures.

Age

Simple febrile seizures occur most commonly in children aged 6 months to 5 years.

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Contributor Information and Disclosures
Author

Robert J Baumann, MD Professor of Neurology and Pediatrics, Department of Neurology, University of Kentucky College of Medicine

Robert J Baumann, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, Child Neurology Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Kenneth J Mack, MD, PhD Senior Associate Consultant, Department of Child and Adolescent Neurology, Mayo Clinic

Kenneth J Mack, MD, PhD is a member of the following medical societies: American Academy of Neurology, Child Neurology Society, Phi Beta Kappa, Society for Neuroscience

Disclosure: Nothing to disclose.

Chief Editor

Amy Kao, MD Attending Neurologist, Children's National Medical Center

Amy Kao, MD is a member of the following medical societies: American Academy of Neurology, American Epilepsy Society, Child Neurology Society

Disclosure: Have stock from Cellectar Biosciences; have stock from Varian medical systems; have stock from Express Scripts.

Additional Contributors

James J Riviello, Jr, MD George Peterkin Endowed Chair in Pediatrics, Professor of Pediatrics, Section of Neurology and Developmental Neuroscience, Professor of Neurology, Peter Kellaway Section of Neurophysiology, Baylor College of Medicine; Chief of Neurophysiology, Director of the Epilepsy and Neurophysiology Program, Texas Children's Hospital

James J Riviello, Jr, MD is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Partner received royalty from Up To Date for section editor.

References
  1. Verity CM, Golding J. Risk of epilepsy after febrile convulsions: a national cohort study. BMJ. 1991 Nov 30. 303(6814):1373-6. [Medline].

  2. Hand L. Delaying childhood vaccines ups postvaccine seizure risk. Medscape Medical News. May 19, 2014. [Full Text].

  3. Hambidge SJ, Newcomer SR, Narwaney KJ, Glanz JM, Daley MF, Xu S, et al. Timely Versus Delayed Early Childhood Vaccination and Seizures. Pediatrics. 2014 May 19. [Medline].

  4. Rosman NP, Colton T, Labazzo J, et al. A controlled trial of diazepam administered during febrile illnesses to prevent recurrence of febrile seizures. N Engl J Med. 1993 Jul 8. 329(2):79-84. [Medline].

  5. Winawer M, Hesdorffer D. Turning on the heat: the search for febrile seizure genes. Neurology. 2004 Nov 23. 63(10):1770-1. [Medline].

  6. Vestergaard M, Pedersen MG, Ostergaard JR, Pedersen CB, Olsen J, Christensen J. Death in children with febrile seizures: a population-based cohort study. Lancet. 2008 Aug 9. 372(9637):457-63. [Medline].

  7. Brooks M. Intranasal Midazolam Works for Seizure Emergencies in Kids. Medscape Medical News. Nov 5 2013. Available at http://www.medscape.com/viewarticle/813827. Accessed: 11/12/13.

  8. Nørgaard M, Ehrenstein V, Mahon BE, Nielsen GL, Rothman KJ, Sørensen HT. Febrile seizures and cognitive function in young adult life: a prevalence study in Danish conscripts. J Pediatr. 2009 Sep. 155(3):404-9. [Medline].

  9. Baumann RJ. Technical report: treatment of the child with simple febrile seizures. Pediatrics. 1999 Jun. 103(6):e86. [Medline].

  10. Boggs W. Increased Risk of Febrile Convulsions With Quadrivalent MMRV Vaccine. Medscape [serial online]. Available at http://www.medscape.com/viewarticle/819454. Accessed: January 27, 2014.

  11. [Guideline] Febrile seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures. Pediatrics. 2008 Jun. 121(6):1281-6. [Medline].

  12. [Guideline] Practice parameter: the neurodiagnostic evaluation of the child with a first simple febrile seizure. American Academy of Pediatrics. Provisional Committee on Quality Improvement, Subcommittee on Febrile Seizures. Pediatrics. 1996 May. 97(5):769-72; discussion 773-5. [Medline].

  13. [Guideline] Riemenschneider TA, Baumann RJ, Duffner PK, et al. Practice parameter: the neurodiagnostic evaluation of the child with a first simple febrile seizure. American Academy of Pediatrics. Provisional Committee on Quality Improvement, Subcommittee on Febrile Seizures. Pediatrics. 1996 May. 97(5):769-72; discussion 773-5. [Medline].

  14. Schink T, Holstiege J, Kowalzik F, Zepp F, Garbe E. Risk of febrile convulsions after MMRV vaccination in comparison to MMR or MMR+V vaccination. Vaccine. 2013 Dec 25. [Medline].

  15. Thoman JE, Duffner PK, Shucard JL. Do serum sodium levels predict febrile seizure recurrence within 24 hours?. Pediatr Neurol. 2004 Nov. 31(5):342-4. [Medline].

 
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