Risk of low serum levels of ionized magnesium in children with febrile seizure

Background: Suboptimal intake of magnesium become prevalent due to the modern diet of processed food low in magnesium. Magnesium may modulate seizure activity by antagonizing excitatory calcium influx through the N-methyl-D-aspartate receptor. Although hyponatremia has been reported to be common in febrile seizures, the most common form of seizure, little is known about the status of serum ionized magnesium. We therefore investigated the status of serum ionized magnesium (iMg²⁺) in children with febrile seizures and compared with controls. Methods: We included all patients from 1 to 6years old who had presented with febrile seizure to the pediatric emergency department at the Korea University Guro Hospital from July 2016 to February 2017. The control group comprised patients admitted to the hospital with febrile respiratory tract infections, but with no history of febrile seizure. Clinical data, blood tests, and electroencephalogram (EEG) results were reviewed using the patients' medical records. Results: A total of 133 patients with febrile seizure and 141 control patients were analyzed in the present study. As a result, hypomagnesemia (<0.50mmol/L) was more common in patients with febrile seizure than in controls (42.9% vs. 6.9%, p<0.001) and it was an independent risk factor for febrile seizure (OR, odds ratio=22.12, 95% CI=9.23-53.02, P<0.001). A receiver operating curve analysis revealed that serum iMg²⁺ levels <0.51mmol/L predicted the presence of febrile seizures with a sensitivity of 45.1% and a specificity of 92.6% (AUC, area under the curve=0.731, 95% confidence interval=0.671-0.791). When the patients with febrile seizure were divided in terms of a serum iMg²⁺ concentration of 0.51mmol/L, there was no difference in clinical features. Conclusions: Hypomagnesemia was more common and serum iMg²⁺ level was lower in patients with febrile seizures than in controls. However, further evidence is needed for the causal relationship between low magnesium and febrile convulsions.