The role of inflammatory markers and calculated osmotic pressure in the classification of febrile seizures

Abstract

Objective: Systemic inflammatory response may contribute to the onset of febrile seizures (FSs). The neutrophil-to-lymphocyte ratio (NLR) has been reported to be useful for differentiating simple and complex FSs in children with a first FS. This study aimed to determine whether easily measurable inflammatory markers were useful for distinguishing between the types of FSs in children with FSs not limited to the first FS.

Patients and methods: We conducted a retrospective study of children aged 6-60 months who were presented to the Atsugi City Hospital in Japan for the treatment of FSs between December 2018 and February 2020. A complex FS was defined as a seizure with multiple seizures during the same febrile illness, prolonged seizures and/or focal seizures. A simple FS was defined as a seizure without the characteristics of complex FS. We assessed complete blood count, C-reactive protein, and calculated osmotic pressure.

Results: A total of 205 children with FSs (simple, 139; complex, 66) fulfilled the inclusion criteria. None of the inflammatory markers, including NLR, could predict the FS type. The median osmotic pressure was 279.0, 278.8, 283.3, and 278.3 mOsm/kg H2O for children with simple, multiple, prolonged, and focal seizures, respectively. Children with prolonged seizures had a significantly higher calculated osmotic pressure than those with simple FSs (p<0.001) and multiple seizures during the same febrile illness (p=0.004).

Conclusions: Easily measurable inflammatory markers, including NLR, were not useful for distinguishing between types of FSs in children. Large multicenter studies are needed to evaluate the association between osmotic pressure and FS.