Spectrum of biochemical abnormalities in neonatal seizures at a tertiary care hospital

Background: Biochemical disturbances occur frequently in neonatal seizures either as an underlying cause or as an associated abnormality. Metabolic disturbances could be more commonly transient and rapidly correctable or less commonly inherited as persistent causes. Objective: To determine the frequency and spectrum of biochemical abnormalities in neonatal seizures of different etiologies.
Materials and Methods: A total of 100 consecutive neonates presenting with seizures from September 2013 to August 2014 were enrolled in the study. Baseline characteristics of convulsing neonate including sex, gestational age, weight, head circumference & length 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 i.e. age at onset of seizures, duration of seizure, number and type of seizure. Venous blood was collected as soon as possible and blood glucose, total serum calcium levels, Na+, K+, Mg and P-levels were done immediately after baby had seizures and before instituting any specific treatment.
Results: Cumulative frequency of neonatal seizures was recorded as 3.9% among admitted neonates in our setup. Around 54% neonates had a biochemical abnormality either alone or in association with other etiologies like hypoxic ischemic encephalopathy (HIE), intracranial hemorrhage (ICH), meningitis and sepsis. 17 neonates (31%) had primary metabolic seizures. Hypocalcemia was the commonest biochemical abnormality in primary metabolic seizures and was present in 70% neonates in this group. Hypoglycemia was the next common abnormality and was present in 41% neonates within this group. 37 neonates (68.5%) had biochemical abnormalities superimposed on other etiologies of neonatal seizures. Metabolic abnormalities were more commonly associated with intracranial hemorrhage (53.8%) and birth asphyxia (50%). Hypoglycemia (22.7%) followed by hypocalcemia (20.5%) were the commonest biochemical abnormalities in these patients. Hyponatremia was found in 20% (n=3) cases of meningitis and in 15.4% (n=2) cases of ICH.
Conclusion: Transient metabolic disturbances occur with a higher frequency in association with other etiologies of neonatal seizures. Early recognition and treatment of these biochemical disturbances is essential for the optimal management and satisfactory outcome. Hypoglycemia and hypocalcemia occur with higher frequency in cases of birth asphyxia, the commonest cause of neonatal seizures. Hypocalcemia followed by hypoglycemia are the commonest transient metabolic disturbances in primary metabolic seizures.