Serum Calcium Levels, Erythrocyte Indices, and Associated Factors in Children with Febrile Seizures

Febrile seizures (FS) are the most common seizures in childhood. In most studies, iron deficiency was associated with FS, whereas serum calcium (Ca) levels were contradictory. This study evaluated the relationships of erythrocyte indices, serum Ca levels, and related factors among children with FS. Prospectively, patients aged six months to five years were included in the complex FS (n = 23), simple FS (n = 22) and febrile without seizure groups (n = 25). Patients with central nervous system infection, previous afebrile seizures, or chronic drug use were excluded. Total and ionized Ca, inorganic phosphate, vitamin D levels, erythrocyte count and indices, hemoglobin, hematocrit, pH, bicarbonate and lactate levels in blood were examined. The cutoff values of variables discriminating between the FS and control groups were established through receiver operating characteristic analysis. In the complex FS group, Ca and mean corpuscular hemoglobin concentration (MCHC) levels were lower than those in the control group (p = 0.004 for both) and albumin levels were lower than those in the simple FS group (p = 0.02). Ca levels were positively correlated with MCHC (r = 0.252, p = 0.039). In the FS group, the proportions of MCHC < 34.1 g/dL, Ca < 9.9 mg/dL, ionized Ca < 1.27 mmol/L and pH < 7.38 were more frequent (p = 0.003, p = 0.005, p = 0.044 and p = 0.035 respectively). Lower Ca and MCHC levels were associated with FS. The positive correlation between Ca and MCHC levels indicates a common pathogenetic mechanism. To our knowledge, the increased proportion of patients with low blood pH level in FS is a novel finding.