Myth #7: Febrile seizures are due to the height of the fever…
Does the height of the fever increase the risk of a febrile seizure? The literature suggests the answer is a big fat…eh…probably not. This is part 7 of a 10-part series where I will be busting what I consider to be the top 10 myths involving pediatric fever.
Bethune P, et al., 19931
This 1993 study set out to identify risk factors predictive of a first febrile seizure
- 75 patients were interviewed with ages ranging between 6 mo – 4 yr following their first febrile seizure
- The investigators found that 2 or more of the following were associated with an increased risk of having a febrile seizure
- FS in 1 or 2 degree relative
- NICU stay >28 days
- Parent reports “slow” development
- Daycare attendance
- If 2 or more of these factors are identified, this study suggests a 28% chance of having a febrile seizure.
Berg AT, Shinnar S, et al., 19952
A similar study from 1995 addressed risk factors for having a febrile seizure.
- 69 patients in this study.
- Risk factors
- Height of temperature
- Family history
- Febrile seizure in a 1stor 2nddegree relative
- Maternal smoking
El-Radhi AS. 19983
Here is an Interesting study from 1998 published in the European Journal of Pediatric Neurology
- They looked at 132 children admitted with their first febrile seizure
- Assessed the characteristics associated with a higher risk for repeat febrile seizure compared to those associated with a lower risk of repeat febrile seizure. Their results are quite interesting.
- Those at higher risk were found to have lower peak temperatures and seizures were the first sign of fever.
- In contrast, those less likely to have a repeat seizure had a higher peak temperature, and their febrile seizure occurred after more than an hour of recognized fever.
So, Can antipyretics prevent recurrence of febrile seizures?
El-Radhi AS, Barry W., 20034
- A 2003 meta-analysis of 12 randomized quasi-controlled studies published in Archive of Disease in Children
- “There is no evidence that antipyretics reduce the risk of subsequent febrile convulsions in at risk children.”
Rosenbloom E, et al., 20135
- 2013 systematic review and meta-analysis of 3 randomized controlled trials
- “No statistically significant difference was found between the antipyretics and the placebo groups in the recurrence rate of febrile seizures.”
- 7% in the antipyretics group and 24.4% in the placebo group had febrile seizure recurrence during follow up.
Strengell T, Uhari M, et al., 20096
- 2009 study of 231 children age 4 mo-4yr
- “Antipyretic agents are ineffective for the prevention of recurrences of febrile seizures and for the lowering of body temperature in patients with a febrile episode that leads to a recurrent febrile seizure.”
- Febrile seizure recurrences occurred in4% in those receiving antipyretic agents and 23.5% in those receiving placebo.
Bottom Line: All found that antipyretics do not prevent febrile seizures. Antipyretics following febrile seizures may provide comfort and symptomatic relief, but should not be recommended to prevent further febrile convulsions.
Let’s summarize the evidence…
- Studies have failed to consistently show that height of the fever is the cause of febrile seizures.
- It is more likely associated with a rapid change of the fever (be it a rising or falling one).
- Febrile seizures are one of the diseases where antipyretic therapy has strongly been advocated…without evidence to back it up.
- Only 3-5% of children with a genetic pre-disposition will get a febrile seizure.
So, for our seventh myth questioning if febrile seizures are due to the height of the fever…I would consider this one Plausible…but ongoing research is really stacking up against it.
References
- Bethune P, Gordon K, et al., (1993). Which child will have a febrile seizure? Am J Dis Child, 147(1):35-9
- Berg AT, Shinnar S, et al., (1995). Risk factors for a first febrile seizure: a matched case-control study. Epilepsia, 36(4):334-41
- El-Radhi AS. (1998). Lower degree of fever at the initial febrile convulsion is associated with increased risk of subsequent convulsions. Eur J Paediatr Neurol, 2(2):91-6
- El-Radhi AS, Barry W., (2003). Do antipyretics prevent febrile convulsions? Arch Dis Child, 88(7):641-2. DOI: 10.1136/adc.88.7.641
- Rosenbloom E, Finkelstein Y, et al., (2013). Do antipyretics prevent the recurrence of febrile seizure in children? A systematic review of randomized controlled trials and meta-analysis.
- Strengell T, Uhari M, et al., (2009). Antipyretic agents for preventing recurrences of febrile seizures: randomized controlled trial. Arch Pediaatr Adolesc Med. 163(9):799-804. doi: 10.1001/achpediatrics.2009.137
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