Prevalence of Biochemical Abnormalities in Neonatal Seizures in Term and Preterm Neonates

Background: The most vulnerable period of life to develop seizures is the neonatal period. These events very often signify serious damage or malfunction of the immature developing central nervous system. Neonatal seizures may arise as a result of diverse etiologies and can have varied presentations. Biochemical abnormalities are commonly observed in neonates who are admitted in neonatal intensive care unit with seizures. Early recognition and treatment of biochemical disturbances is essential for optimal management and satisfactory long-term outcome.

Objective: To assess clinical types and importance of biochemical abnormalities in neonatal seizures and to evaluate clinical type & time of onset of seizures in term and preterm neonates.

Methods: A prospective observational study, where 100 neonates presenting with seizures admitted to neonatal intensive care unit of Jagadguru Jayadeva Murugarajendra Medical College, Davangere, from September 2015 to August 2017 were enrolled in the study. The detailed history along with clinical examination, baseline characteristics of convulsing neonate were recorded at admission. Clinical details of each seizure episode reported by the mother and subsequently observed by the resident doctors on duty were recorded. The relevant biochemical investigations were done immediately after baby had seizures and before instituting any specific treatment. The descriptive statistics such as mean and standard deviation (SD) for continuous variables, frequencies and percentages were calculated for categorical variables. The association between gestational age and other categorical variables were analyzed using chi-square test of independence. The comparison of mean of various quantitative variables was analyzed using ANOVA test. Etiology of neonatal seizures and associated biochemical abnormalities were diagnosed.

Results: In the present study, out of 100 neonates studied, 64 were full term of which 49(76.5%) were appropriate for gestational age and 15(23.5%) were small gestational age, whereas 36 cases were preterm. Most neonatal seizures occur in first 3 days of life, i.e. 59%. Most of them occurred on first day of life (34%). Birth asphyxia was the cause of neonatal seizures in 82.35% neonates who developed seizures on day-1 of life. Birth asphyxia and septicemia are common cause of neonatal seizures in our study (38 cases each), followed by pure metabolic disturbances 19%. In pure metabolic seizures, hypoglycemia (47.8%) is most common more in preterm babies (55%) followed by hypocalcemia. In cases of non- metabolic seizures, which showed associated biochemical abnormalities, hypoglycemia was most common abnormality 23 of 52 cases (44.2%). 12 cases (52.1%) are associated with birth asphyxia and 11 cases (47.9%) are associated with septicemia. Subtle seizures were most common type of seizures in our study, followed by focal clonic, multifocal clonic, generalized tonic, subtle with GTC and subtle with clonic.

Conclusion: Biochemical abnormalities are common in neonatal seizures and often go unorganized. These abnormalities may significantly contribute to seizure activity correction of these abnormalities work up is necessary for all cases of neonatal seizures.