Febrile seizures are one of the most common pediatric emergencies and are usually associated with high fever in children between six months and five years of age. The exact pathophysiology is unknown. Simple febrile seizures are the most common type; they are usually generalized, last under 15 minutes, and do not recur within 24 hours. Complex febrile seizures have a focal onset, last longer than 15 minutes, or recur within 24 hours. Diagnostic examination of simple febrile seizures focuses on addressing the cause of fever. Further diagnostics are required for patients with complex febrile seizures, particularly to exclude herpes encephalitis, and include lumbar puncture, CT scan, and/or EEG. Most febrile seizures end spontaneously and do not require any treatment. If seizures persist after five minutes or present as complex febrile seizures, however, IV benzodiazepines are the treatment of choice. Caregivers should be reassured as the prognosis of febrile seizures is good, with the risk of epilepsy being less than 10%.
Febrile seizures are seizures that are associated with fever; (mainly temperatures exceeding 38°C (100.4°F); ) in the absence of CNS infection, metabolic abnormalities, or a history of afebrile seizures.
- Peak incidence: : 2nd year of life; most commonly occurs between 6 months and 5 years of age
- Prevalence: Febrile seizures occur in ∼ 4% of all children.
Epidemiological data refers to the US, unless otherwise specified.
- Genetic predisposition
- High fever (> 40°C (104°F))
- Viral infection (e.g., HHV-6, influenza)
- Recent immunization (especially MMR and TDap)
|Simple febrile seizure (∼75%)||Complex febrile seizure* (∼25%)|
|Duration and frequency|| || |
| || |
|Postictal phase|| |
|*Febrile seizures are considered complex if at least one of the criteria are met!|
- Determine the cause of fever
- Additional diagnostic steps: for complex febrile seizures and/or abnormal neurological examination
|Differential diagnoses of seizures|
|Febrile seizures||Non-epileptic events or movements||CNS infection (e.g., bacterial meningitis)||Epilepsy|
The differential diagnoses listed here are not exhaustive.
- Abortive therapy
- Reassure caregivers and provide information
- After a febrile seizure, initiate antipyretic therapy (NSAIDs and acetaminophen) at an early stage (temperatures from 38°C (100.4°F)) as they restore the central thermoregulatory setpoint back to normal by reducing the synthesis of prostaglandin E2.
Febrile seizures primarily occur during the rise in temperature; therefore, prophylactic measures are often too late because a seizure cannot be anticipated! Long-term continuous or intermittent prophylaxis with anticonvulsant drugs (e.g., phenobarbital) or diazepam is not recommended.
- The risk of recurrent, simple febrile seizures is 30%.
- Risk of developing epilepsy:
- Risk factors for recurrence: