AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Febrile seizures are the most common type of seizures observed in the pediatric age group.

Although described by the ancient Greeks, it was not until this century that febrile seizures were recognized as a distinct syndrome separate from epilepsy. In 1980, a consensus conference held by the National Institutes of Health described a febrile seizure as, "An event in infancy or childhood usually occurring between three months and five years of age, associated with fever, but without evidence of intracranial infection or defined cause." It does not exclude children with prior neurological impairment and neither provides specific temperature criteria nor defines a "seizure."

Febrile seizures are usually benign but can cause considerable parental anxiety. Recent studies have defined a group of patients at higher risk for febrile seizures and a group likely to have recurrence of febrile seizures.

For other information, see Medscape's Pediatrics Specialty page.

For related CME activities, see CME/CE - Neonatal Emergencies and CME/CE - Commonly Administered Vaccines and Associated Illnesses.

Pathophysiology

Febrile seizures occur in young children at a time in their development when the seizure threshold is low. This is a time when young children are susceptible to frequent childhood infections such as upper respiratory infection, otitis media, viral syndrome, and they respond with comparably higher temperatures. Animal studies suggest a possible role of endogenous pyrogens, such as interleukin 1, that, by increasing neuronal excitability, may link fever and seizure activity. Preliminary studies in children appear to support the hypothesis that the cytokine network is activated and may have a role in the pathogenesis of febrile seizures, but the precise clinical and pathological significance of these observations is not yet clear.

Febrile seizures are divided into 2 types: simple febrile seizures (which are generalized, last <15 min and do not recur within 24 h) and complex febrile seizures (which are prolonged, recur more than once in 24 h, or are focal). Complex febrile seizures may indicate a more serious disease process, such as meningitis, abscess, or encephalitis. Viral illnesses are the predominant cause of febrile seizures. Recent literature documented the presence of human herpes simplex virus 6 (HHSV-6) as the etiologic agent in roseola in about 20% of a group of patients presenting with their first febrile seizures. Shigella gastroenteritis also has been associated with febrile seizures. One study suggests a relationship between recurrent febrile seizures and influenza A.

Genetics: Febrile seizures tend to occur in families. In a child with febrile seizure, the risk of febrile seizure is 10% for the sibling and almost 50% for the sibling if a parent has febrile seizures as well. Although clear evidence exists for a genetic basis of febrile seizures, the mode of inheritance is unclear.

Frequency

United States

Between 2% and 5% of children have febrile seizures by their fifth birthday. About one third of these patients have at least one recurrence.

International

A similar rate of febrile seizures is found in Western Europe. The incidence elsewhere in the world varies between 5 and 10% for India, 8.8% for Japan, 14% for Guam, 0.35% for Hong Kong, and 0.5-1.5% for China.

Mortality/Morbidity

• Febrile seizures are usually benign.
• Children with febrile seizures have a slightly higher incidence of epilepsy compared with the general population (2% vs 1%).
• Risk factors for epilepsy later in life include complex febrile seizure, family history of epilepsy or neurologic abnormality, and developmental delay. Patients with 2 risk factors have up to a 10% chance of developing afebrile seizures.

Race

Febrile seizures occur in all races.

Sex

Some studies demonstrate a slight male predominance.

Age

By definition, febrile seizures occur in children aged 3 months to 5 years.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• The type of seizure (generalized or focal) and its duration should be described to help differentiate between simple and complex febrile seizures.
• Focus on the history of fever, duration of fever, and potential exposures to illness.
• A history of the cause of fever (eg, viral illnesses, gastroenteritis) should be elucidated.
• Recent antibiotic use is particularly important because partially treated meningitis must be considered.
• A history of seizures, neurologic problems, developmental delay, or other potential causes of seizure (eg, trauma, ingestion) should be sought.

Physical

• The underlying cause for the fever should be sought.
• A careful physical examination often reveals otitis media, pharyngitis, or a viral exanthem.
• Serial evaluations of the patient's neurologic status are essential.
• Check for meningeal signs as well as for signs of trauma or toxic ingestion.

Causes

• Risk factors for developing febrile seizures
• • Family history of febrile seizures
  • High temperature
  • Parental report of developmental delay
  • Neonatal discharge at an age greater than 28 days (suggesting perinatal illness requiring hospitalization)
  • Daycare attendance
  • Presence of 2 of these risk factors increases the probability of a first febrile seizure to about 30%.
  • Maternal alcohol intake and smoking during pregnancy has a 2-fold increased risk.
  • Interestingly, no data support the theory that a rapid rise in temperature is a cause of febrile seizures.
• About one third of all children with a first febrile seizure experience recurrent seizures.
• • Risk factors for recurrent febrile seizures include the following:
  • • Young age at time of first febrile seizure
    • Relatively low fever at time of first seizure
    • Family history of a febrile seizure in a first degree relative
    • Brief duration between fever onset and initial seizure
  • Patients with all 4 risk factors have greater than 70% chance of recurrence. Patients with no risk factors have less than a 20% chance of recurrence.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Routine laboratory studies usually are not indicated unless they are performed as part of a search for the source of a fever.
• Electrolytes assessments are rarely helpful in the evaluation of febrile seizures.
• Patients with febrile seizures have an incidence of bacteremia similar to patients with fever alone.

Imaging Studies

• A CT scan usually is not necessary in the evaluation of a child with a first simple febrile seizure.
• A CT scan should be considered in patients with complex febrile seizures. However, a  study by Teng et al analyzed data in 71 children with first complex febrile seizure.¹ Fifty-one (72%) had a single complex feature (20 focal, 22 multiple, and 9 prolonged), and 20 (28%) had multiple complex features. None of the 71 patients (1-sided 95% confidence interval, 4%) had intracranial pathologic conditions that required emergency neurosurgical or medical intervention. Forty-six had normal acute scans, the rest were normal on clinical follow up without a scan. The confidence interval means that this study cannot exclude a risk of intracranial pathology of 4% or less.

Other Tests

• An electroencephalogram (EEG) usually is not necessary in the routine evaluation of a child with a first simple febrile seizure.

Procedures

• Lumbar puncture
• • Controversy exists regarding the need for a lumbar puncture in a child presenting with a simple febrile seizure.
  • Certainly, meningitis can present with a seizure, although the seizure usually is not the only sign of meningitis. Patients who have a first time febrile seizure and do not have a rapidly improving mental status (short postictal period) should be evaluated for meningitis.
  • Several reviews of the medical literature report less than 5% incidence of meningitis in children presenting with seizures and fever.
  • Risk factors for meningitis in patients presenting with seizure and fever include the following:
  • • A physician visit within 48 hours
    • Seizure activity at the time of arrival in the ED
    • Focal seizure, suspicious physical examination findings (eg, rash, petechiae) cyanosis, hypotension, or grunting
    • Abnormal neurologic examination
  • In 1996, the American Academy of Pediatrics (AAP) recommended that a lumbar puncture be strongly considered in patients younger than 12 months presenting with fever and seizure.² The AAP also recommended that a lumbar puncture be considered in patients aged 12-18 months. A lumber puncture is not routinely necessary in patients older than 18 months. This recommendation is conservative, but it takes into account the difficulty in recognizing meningitis in infants and young children and the range of experience in the evaluation of pediatric patients among healthcare providers.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Prehospital Care

• Patients with active seizures should be treated with airway management, high flow oxygen, supportive care, and anticonvulsants as necessary.
• Patients who are postictal should receive supportive care, and antipyretics as appropriate.

Emergency Department Care

• Patients presenting with status epilepticus should be treated with airway management and anticonvulsants as necessary.
• Patients presenting with history and physical examination findings consistent with a simple febrile seizure should have frequent neurologic examinations to monitor mental status.
• Other causes of seizure should be ruled out.
• The cause of the febrile illness should be sought and treated.
• Antipyretics should be considered.
• Parental anxiety needs to be addressed.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Patients presenting in status epilepticus can be treated with routine seizure medications, including benzodiazepines, phenytoin, and phenobarbital. For further discussion on the treatment of seizures, see Pediatrics, Status Epilepticus.

Drug Category: Antipyretics

Antipyretics should be used in patients who appear uncomfortable secondary to fever. Antipyretics do not appear to prevent recurrence of febrile seizures.

Drug Name	Ibuprofen (Advil, Motrin)
Description	One of the few NSAIDs indicated for reduction of fever. Inhibits the formation of prostaglandins.
Adult Dose	200-400 mg PO q4-6h while symptoms persist; not to exceed 3.2 g/d
Pediatric Dose	5-10 mg/kg/dose PO q6-8h prn; not to exceed 40 mg/kg/d or 2.4 g/d
Contraindications	Documented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, high risk of bleeding
Interactions	Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently
Pregnancy	B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions	Caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy

Drug Category: Anticonvulsant agents

Prophylactic treatment with an anticonvulsant agent may be considered for subsequent fever episodes.

Drug Name	Lorazepam (Ativan)
Description	Sedative hypnotic with short onset of effects and relatively long half-life. By increasing the action of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter in the brain, may depress all levels of CNS, including limbic and reticular formation. Important to monitor patient's blood pressure after administering dose. Adjust as necessary.
Adult Dose	Disease state not seen in adults; adult dose is 4 mg/dose IV slowly over 2-5 min and repeat in 10-15 min prn; cumulative dose of 8 mg/d typically considered maximum 1-10 mg/d PO/IV/IM divided bid/tid
Pediatric Dose	Infants and children: 0.1 mg/kg IV slowly over 2-5 min; repeat prn in 10-15 min at 0.05 mg/kg; not to exceed 4 mg/dose Adolescents: 0.07 mg/kg IV slowly over 2-5 min and repeat in 10-15 min prn; not to exceed 4 mg/dose
Contraindications	Documented hypersensitivity; preexisting CNS depression, hypotension, and narrow-angle glaucoma; reversal agents (eg, flumazenil) contraindicated when lorazepam used for life-threatening conditions (eg, control of intracranial pressure or status epilepticus)
Interactions	Toxicity of benzodiazepines in CNS increases when used concurrently with alcohol, phenothiazines, barbiturates, and MAO inhibitors
Pregnancy	D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions	May lead to hypoventilation or apnea (flumazenil contraindicated); caution in renal or hepatic impairment

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• The decision to admit should be individualized, but admission usually is not necessary.
• Most patients should be observed in the ED until awake and alert.
• Conditions requiring admission of the patient include the following:
• • More than 1 seizure within 24 hours
  • Unstable clinical status
  • Lethargy beyond the postictal period
  • Uncertain home situation
  • Unclear follow-up care

Further Outpatient Care

• Arrange for medical reevaluation of discharged patients and parental education in a follow-up appointment within 24-48 hours.

In/Out Patient Meds

• Discharge medications include antipyretics and (if indicated) antibiotics.
• Prophylaxis for possible recurrence of febrile seizures is controversial.
• • No evidence indicates that antipyretics prevent the recurrence of febrile seizures.
  • Phenobarbital and valproic acid can be given daily and are effective, but they are associated with multiple adverse effects. Carbamazepine and phenytoin are not effective in preventing recurrent febrile seizures.
  • Some studies report that diazepam, given orally or rectally every 8 hours during febrile illnesses, is effective in preventing recurrence of febrile seizures.
  • Diazepam is associated with ataxia and lethargy; thus, it may make the evaluation of the febrile child more difficult.
  • Many clinicians believe that the risk of treating prophylactically for febrile seizures outweighs the benefits.
  • A decision to place a child on prophylactic medication should be made in conjunction with the primary physician.

Deterrence/Prevention

• Given a more established role of influenza A in the etiology of febrile seizure, both acute and recurrent, there may, perhaps, be a role of vaccination against influenza A in the flu season, to prevent development of both acute and recurrent febrile seizures.³

Prognosis

• Although commonly frightening to parents, febrile seizures are benign events.
• Recurrent febrile seizures occur in about one third of children having a first febrile seizure.
• • Risk factors for recurrent febrile seizures include young age at time of first febrile seizure, relatively low fever at time of presentation with first seizure, family history of a febrile seizure in a first-degree relative, and brief duration between fever onset and initial seizure.
  • Patients with all 4 risk factors have a greater than 70% chance of recurrence. Patients with no risk factors have a less than 20% chance of recurrence.
• Children with a febrile seizure have a slight increase in the incidence of epilepsy compared with the general population (1% vs 0.5%).
• • Risk factors for epilepsy later in life include complex febrile seizure, family history of epilepsy or neurologic abnormality, and developmental delay.
  • Patients with 2 risk factors have up to 10% chance of developing afebrile seizures.

Patient Education

• Parents should be taught what to do if their child has another seizure.
• The parent should be advised to call for assistance if the seizure lasts longer than 10 minutes or if the postictal period lasts longer than 30 minutes.
• Parents should be counseled on the benign nature of febrile seizures.
• Parents should be reassured that simple febrile seizures do not lead to neurologic problems or developmental delay.
• For excellent patient education resources, visit eMedicine's Brain and Nervous System Center. Also, see eMedicine's patient education articles Seizures and Fever and Seizures in Children.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Meningitis must be ruled out by clinical examination or by lumbar puncture. This is more difficult when the patient is taking oral antibiotics at the time of seizure.
• Parents should be taught what to do if a seizure reoccurs.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

1. Teng D, Dayan P, Tyler S, et al. Risk of intracranial pathologic conditions requiring emergency intervention after a first complex febrile seizure episode among children. Pediatrics. Feb 2006;117(2):304-8. [Medline].
2. American Academy of Pediatrics. 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. May 1996;97(5):769-72; discussion 773-5. [Medline].
3. Kwong KL, Lam SY, Que TL, Wong SN. Influenza A and febrile seizures in childhood. Pediatr Neurol. Dec 2006;35(6):395-9. [Medline].
4. Aicardi J, ed. Febrile Convulsions in Epilepsy in Children. 2^nd ed. New York: Raven Press; 1994:253.
5. American Academy of Pediatrics. Practice parameter: long-term treatment of the child with simple febrile seizures. American Academy of Pediatrics. Committee on Quality Improvement, Subcommittee on Febrile Seizures. Pediatrics. Jun 1999;103(6 Pt 1):1307-9. [Medline].
6. Berg AT. Are febrile seizures provoked by a rapid rise in temperature?. Am J Dis Child. Oct 1993;147(10):1101-3. [Medline].
7. Berg AT, Shinnar S, Darefsky AS, et al. Predictors of recurrent febrile seizures. A prospective cohort study. Arch Pediatr Adolesc Med. Apr 1997;151(4):371-8. [Medline].
8. Bethune P, Gordon K, Dooley J, et al. Which child will have a febrile seizure?. Am J Dis Child. Jan 1993;147(1):35-9. [Medline].
9. Chung B, Wat LC, Wong V. Febrile seizures in southern Chinese children: incidence and recurrence. Pediatr Neurol. Feb 2006;34(2):121-6. [Medline].
10. Gatti S, Vezzani A, Bartfai T. Mechanisms of fever and febrile seizures: putative role of the interleukin-1 system. In: Baram TZ, Shinnar S eds. Febrile Seizures. San Diego, Ca: Academic Press; 2002:169-88.
11. Haspolat S, Mihci E, Coskun M, et al. Interleukin-1beta, tumor necrosis factor-alpha, and nitrite levels in febrile seizures. J Child Neurol. Oct 2002;17(10):749-51. [Medline].
12. Hauser WA. The prevalence and incidence of convulsive disorders in children. Epilepsia. 1994;35 Suppl 2:S1-6. [Medline].
13. Hirtz DG. Febrile seizures. Pediatr Rev. Jan 1997;18(1):5-8; quiz 9. [Medline].
14. Joffe A, McCormick M, DeAngelis C. Which children with febrile seizures need lumbar puncture? A decision analysis approach. Am J Dis Child. Dec 1983;137(12):1153-6. [Medline].
15. Knudsen FU. Febrile seizures--treatment and outcome. Brain Dev. Nov-Dec 1996;18(6):438-49. [Medline].
16. 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. Jul 8 1993;329(2):79-84. [Medline].
17. Stenklyft PH, Carmona M. Febrile seizures. Emerg Med Clin North Am. Nov 1994;12(4):989-99. [Medline].
18. van Stuijvenberg M, Derksen-Lubsen G, Steyerberg EW, et al. Randomized, controlled trial of ibuprofen syrup administered during febrile illnesses to prevent febrile seizure recurrences. Pediatrics. Nov 1998;102(5):E51. [Medline].
19. Waruiru C, Appleton R. Febrile seizures: an update. Arch Dis Child. Aug 2004;89(8):751-6. [Medline].

Article Last Updated: Mar 28, 2008