Study of Serum and CSF Lactate Dehydrogenase in Simple and Complex Febrile Seizures in Children

Objectives: This study investigates lactate dehydrogenase (LDH) levels in both serum and cerebrospinal fluid (CSF) among pediatric patients experiencing febrile seizures (FS) and evaluates its diagnostic and predictive performance. Materials and Methods: A total of 100 children aged 6–60 months were enrolled: 62 with simple febrile seizures (SFS), 38 with complex febrile seizures (CFS), and 50 febrile children without seizures as controls. The CFS group was subdivided by the seizure type (focal, prolonged, and recurrent). Serum and CSF-LDH were measured, and receiver operating characteristic (ROC) analysis assessed the diagnostic accuracy of CSF-LDH for CFS. Multivariable linear regression explored the associations with seizure duration, anticonvulsant use, fever magnitude, and magnetic resonance imaging (MRI) abnormalities. Results: CSF-LDH was significantly higher in CFS patients (44 ± 16 U/L) than controls (26 ± 8 U/L, P < 0.001), particularly in prolonged seizures. ROC analysis demonstrated good diagnostic accuracy of CSF-LDH for distinguishing CFS from SFS (area under the curve = 0.79; 95% confidence interval = 0.72–0.86; sensitivity = 78.3%; specificity = 72.5%). In multivariable regression, CSF-LDH independently correlated with prolonged seizures ( β =34, P = 0.016) and MRI abnormalities ( β =28, P = 0.031). Mean CSF-LDH levels were significantly elevated in MRI-positive compared to MRI-negative patients across subtypes. Analysis of variance showed significant differences in LDH between subtypes for both MRI-positive ( P < 0.001) and MRI-negative groups. Conclusion: Elevated CSF-LDH concentrations may indicate neuronal damage in children with CFS and can aid in differentiating FS subtypes.