Type your tag names separated by a space and hit enter

Seizures, Febrile

Seizures, Febrile is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or purchase a subscription.

Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:

Medicine Central

-- The first section of this topic is shown below --

Basics

Description

Febrile seizures occur in children aged 6 months to 5 years with fever ≥100.4°F (38°C) and absence of underlying neurologic abnormality, metabolic condition, or intracranial infection. Three distinct categories (1):

  • Simple febrile seizure (70–75%; must meet all criteria)
    • Generalized clonic or tonic–clonic seizure activity without focal features
    • Duration <15 minutes
    • Does not recur within 24 hours
    • Resolves spontaneously
    • No history of previous afebrile seizure or seizure disorder
  • Complex (CFS) (20–25%; only one criterion must be met)
    • Partial seizure, focal activity
    • Duration >15 minutes but <30 minutes
    • Recurrence within 24 hours
    • Postictal neurologic abnormalities (e.g., Todd paresis) (2)
  • Febrile status epilepticus (FSE) (5%)
    • Lasts >30 minutes

Epidemiology

Incidence
  • Approximately 500,000 febrile seizures occur in the United States annually.
  • Peak incidence is 18 months of age (2).
  • Only 6% of febrile seizures occur before age 6 months, and 4% of febrile seizures occur after age 3 years (3).
  • Bimodal seasonal pattern that mirrors peaks of febrile respiratory (November to January) and gastrointestinal infections (June to August) (2)

Prevalence
  • 2–5% of children in the white population aged 6 months to 3 years in United States and Western Europe (3)
  • Cumulative incidence varies in other populations (0.5–14%) (1).

Etiology and Pathophysiology

A variety of mechanisms have been proposed:

  • A lower baseline seizure threshold in the age group affected by febrile seizures
  • Familial genotypes may influence seizure thresholds.
  • Fever may alter ion channel activity, resulting in increased circuit excitability.
  • Cytokines released secondary to infection, specifically interleukin (IL)-1β, increase neuronal activity.
Genetics
  • Evidence for genetic association:
    • Greater concordance in monozygotic than dizygotic twins
    • 25–40% of cases have positive family history (3).
    • Risk of febrile seizure with a previously affected sibling is increased.
    • Having two affected parents doubles a child’s risk of febrile seizure.
    • Mode of inheritance is multifactorial, although autosomal dominant inheritance reported (2).
  • Several rare familial epileptic syndromes present with febrile seizure.

Risk Factors

  • Any condition causing fever
  • Risk increases with the number of affected first-degree relatives.
  • Risk is increased for male children (1).
  • Recent vaccination
    • As febrile seizures are a benign entity, the benefits of vaccination outweigh the risk.
    • Possible increased risk with vaccinations, mainly MMR and DTaP, is a matter of much debate (3), and absolute vaccination-associated risk is very low.
  • Prenatal exposure to alcohol and tobacco, daycare attendance, premature birth, developmental delay, and prolonged NICU stay
  • Children with iron deficiency anemia may have increased risk for febrile seizures. Consider checking for anemia if the history suggests a risk for iron deficiency (4)[C].

General Prevention

Prevention is not usually indicated given the benign nature of this condition, lack of effective interventions, and side effects of prophylactic medications.

Commonly Associated Conditions

  • Viral infections: Common pathogens include human herpesvirus 6, influenza, parainfluenza, adenovirus, and respiratory syncytial virus (RSV).
    • HHV-6 infection found in 30% of FSE in one study (3)
  • Bacterial infections: Frequently associated infections include otitis media, pharyngitis, urinary tract infection (UTI), pneumonia, and gastroenteritis.

-- To view the remaining sections of this topic, please or purchase a subscription --

Citation

Stephens, Mark B., et al., editors. "Seizures, Febrile." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117585/all/Seizures__Febrile.
Seizures, Febrile. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117585/all/Seizures__Febrile. Accessed April 26, 2019.
Seizures, Febrile. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117585/all/Seizures__Febrile
Seizures, Febrile [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 April 26]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117585/all/Seizures__Febrile.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Seizures, Febrile ID - 117585 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117585/all/Seizures__Febrile PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -