Utility of laboratory studies in seizures of children older than one month of age

Seizure is the most common paediatric neurological disease which occurs in ten percent of children. In approaching a convulsive patient, finding the causes of seizure is essential, and the patient's history as well as the physical examination are important. The role of routine laboratory tests for children's seizures (except neonates) is undetermined, but checking for serum sodium, glucose, calcium and urea routinely has been advised. The purpose of this study was to determine the diagnostic efficacy of these serum chemistry tests in the seizures of children older than one month of age. In this descriptive, retrospective study, medical records of 302 hospitalised children with seizure were reviewed. Results of laboratory tests, like sodium, calcium, blood glucose and urea levels, pertinent history and physical examination, and the change in patient management based on serum chemistry test results, were analysed. All the children in the study were classified as having seizure with or without fever. In 302 hospitalised children with seizure, about ten percent of 938 tests were abnormal. 27.7 percent of these abnormal results were seen in 1-12-month-old infants. Only 11 percent of abnormal tests (1.3 percent of total tests) might have caused a seizure. Also, 0.2 percent of the results could not be predicted from the history or physical examination, which was conducted in patients younger than one year of age. Routine determination of serum chemistry values in seizures of children does not contribute to therapy, and are costly and time-consuming. It may not be helpful and informative unless the patient is less than one year of age.