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A febrile seizure is a seizure accompanied by fever (temperature ≥38°C / 100.4°F) without evidence of CNS infection, occurring in children aged 6 months to 5-6 years. It is thought that the rapid rise or defervescence of fever (rather than the absolute peak temperature) is the trigger. About 2-5% of children will experience at least one febrile seizure in their lifetime.
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Focal onset, OR
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Duration > 15 minutes, OR
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Recurs within 24 hours, OR
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Occurs outside the typical age range (< 6 months or > 6 years)
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Harriet Lane Handbook, 23rd ed., p. 739-741
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Tintinalli's Emergency Medicine
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Pre-existing neurological disorder or developmental delay
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Family history of epilepsy
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Complex febrile seizure (focal, prolonged, or repeated in same day)
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First febrile seizure before 12 months of age
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Todd's paralysis, focal neurologic findings, or abnormal EEG/imaging
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Goodman & Gilman's, p. (block6)
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Tintinalli's, p. 936
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Viral infections (most common) - especially roseola (HHV-6)
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Ear infections (acute otitis media)
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Upper respiratory tract infections
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Post-vaccination fever (MMR, MMRV - small increased risk; the risk is outweighed by vaccine benefits)
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Goodman & Gilman's
Note: Children > 12 months can usually be assessed clinically for meningitis. The incidence of bacterial meningitis after simple febrile seizure is very low (0.4-1.2%).
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Obtain EEG
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Consider non-emergent MRI (to evaluate for focal lesion)
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LP if concern for CNS infection
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Routine blood tests and imaging are still not mandatory in the absence of signs/symptoms
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Harriet Lane Handbook, Rosen's, Tintinalli's
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Chronic anticonvulsant prophylaxis is NOT recommended - side effects (e.g., phenobarbital causes cognitive effects) outweigh the modest risk-reduction benefit
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Prophylactic anticonvulsants would only treat the febrile seizure, not prevent later epilepsy
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For high-risk children with recurrent febrile seizures: rectal or oral diazepam at the time of fever may prevent recurrence and avoids chronic therapy side effects
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For complex febrile seizures: consider prescribing rectal diazepam for home emergency use
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Goodman & Gilman's, Swanson's Family Medicine Review, Harriet Lane Handbook