Journal of Pediatric Neurosciences
LETTER TO EDITOR
Year
: 2020  |  Volume : 15  |  Issue : 3  |  Page : 345--346

Relationship between serum sodium levels and febrile seizure recurrence in children


Prateek K Panda, Indar K Sharawat 
 Pediatric Neurology Division, Department of Pediatrics, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Correspondence Address:
Dr. Indar K Sharawat
Pediatric Neurology Division, Department of Pediatrics, All India Institute of Medical Sciences, Rishikesh, Uttarakhand.
India




How to cite this article:
Panda PK, Sharawat IK. Relationship between serum sodium levels and febrile seizure recurrence in children.J Pediatr Neurosci 2020;15:345-346


How to cite this URL:
Panda PK, Sharawat IK. Relationship between serum sodium levels and febrile seizure recurrence in children. J Pediatr Neurosci [serial online] 2020 [cited 2021 Jan 18 ];15:345-346
Available from: https://www.pediatricneurosciences.com/text.asp?2020/15/3/345/300032


Full Text



Dear Editor

We read with great interest the recently published article entitled “Relation between febrile seizure recurrence and hyponatremia in children: A single-center trial” by Navaeifar et al.[1] The authors have shown in this study that although serum sodium level was less in febrile seizure group as compared to children with unprovoked seizures, no significant difference was observed between serum sodium levels among children with simple and recurrent febrile seizures.[1] We wish to add a few points.

The relevance of serum sodium levels in children with febrile seizures continues to be a controversial topic. Although even the American Academy of Pediatrics[2] and other studies[3] agree that serum sodium level is lower in children with febrile seizures as compared to controls, they do not recommend routinely measuring serum sodium levels in all children with febrile seizures. In this study, authors have shown significant differences in baseline characteristics such as age at presentation, but they have not taken these confounding factors into account while comparing serum sodium levels in the three groups. In such cases, multivariate logistic regression analyses would have been more informative regarding true differences between groups[4] and whether they are independent or dependent variables for seizure occurrence.

Second, the authors have measured the differences between the two groups assuming serum sodium level as a continuous variable. As the overall prevalence of hyponatremia was only 6.6%, low serum sodium values in those children might be compensated in the analysis by normal sodium values in the rest of the participants in a large number. The authors have not mentioned the exact prevalence of hyponatremia in both groups and whether the difference was statistically significant. This would have added to the clinical relevance of the article. Also, there is no mention regarding whether the difference between different underlying etiologies for acute febrile illness leading to simple and recurrent febrile seizures was statistically significant or not. Some illnesses, such as acute gastroenteritis, are more likely to affect serum sodium as compared to other etiologies such as vaccination and acute respiratory illnesses.

Moreover, the authors have mentioned that only children with generalized seizures were included in the study, whereas in the results, they have mentioned most of the participants had generalized seizures meaning some of the participants also had focal seizures. Both of these conflicting statements need to be clarified regarding the true semiology of seizure in participants. Also, the authors have not mentioned the exact method by which serum sodium level was measured. Studies have shown discrepancies between sodium concentrations measured by different dilutional and direct ion-selective electrode analyzers.[5] Even it has been shown that arterial blood gas analyzers are not quite reliable, not equivalent to auto analyzers, and cannot be used interchangeably.[6] Thus, the exact method by which serum sodium level was measured needs to be taken into account before extrapolating the study results into clinical practice.

Lastly, there is a possibility that low serum sodium levels might not be an independent predictor of febrile seizure, and it might be due to only raised body temperature, and hyponatremia might be predominantly due to dehydration and poor oral intake.[6] This could have been determined if the authors would have measured serum sodium level in some age and sex-matched febrile controls without a seizure. The title of the study mentions this as a trial, whereas in reality, it is a prospective study without any new therapeutic intervention, and the study is not registered with any trial registration authority.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Navaeifar MR, Abbaskhanian A, Farmanbarborji A Relation between febrile seizure recurrence and hyponatremia in children: a single-center trial. J Pediatr Neurosci 2020;15:5-8.
2Subcommittee on Febrile Seizures; American Academy of Pediatrics. Neurodiagnostic evaluation of the child with a simple febrile seizure. Pediatrics 2011;127:389-94.
3Sharawat IK, Singh J, Dawman L, Singh A Evaluation of risk factors associated with first episode febrile seizure. J Clin Diagn Res 2016;10:SC01-5.
4Sharawat IK, Dawman L Bone mineral density and its correlation with vitamin D status in healthy school-going children of Western India. Arch Osteoporos 2019;14:13.
5Hanna M, Saberi MS Incidence of hyponatremia in children with gastroenteritis treated with hypotonic intravenous fluids. Pediatr Nephrol 2010;25:1471-5.
6Yilmaz S, Uysal HB, Avcil M, Yilmaz M, Dağlı B, Bakış M, et al. Comparison of different methods for measurement of electrolytes in patients admitted to the intensive care unit. Saudi Med J 2016;37:262-7.