Clinico-Biochemical Profile of Neonatal Seizure

Objectives: The present study was undertaken to study the incidence, etiological factor, and days of onset, clinical types and biochemical abnormalities in babies having neonatal seizures. Materials and Methods: This is a retrospective, observational hospital based study. Ninety neonates, who developed seizures before 28 days of life and admitted to neonatal intensive care unit and nursery with neonatal seizure, were evaluated for incidence, etiological factor, clinical types and biochemical abnormalities found in neonatal seizure. The variables were analysed using ChiSquare and student ttest. Results: The incidence of neonatal seizure was 10.3/ 1000 live births. The seizures were common in male babies. 65 (72.2%) neonates were born to multiparous women while 35 (38%) were born to primigravidas. In birth asphyxia (n= 40), the most common type of seizure observed was subtle seizure 20 (50%), followed by focal clonic 10 (25%) and multifocal clonic 5 (12.5%). Tonic type of seizure was observed in 3 (7.5%) and myoclonic in 2 (5%). Meningitis and septicaemia was the second most common cause of neonatal seizure observed in our study. Among metabolic abnormalities hypoglycaemia was found in 20 (22%) and hypocalcaemia in 10 (11%). Conclusion: The commonest cause of seizure was birth asphyxia presenting within 72 hours of life. Among infection septicaemia and meningitis was the most common cause leading to neonatal seizure. Among biochemical abnormalities the most common cause of seizure observed in our study was hypoglycaemia and hypocalcaemia. Subtle seizures were the commonest type of seizure observed in this study.


Introduction:
The presence of seizure does not constitute a diagnoses but it is a symptom of an underlying central nervous system disorder due to systemic or biochemical disturbances.Biochemical disturbances occur frequently in the neonatal seizures either as an underlying cause or as an associated abnormality.In their presence, it is difficult to control seizure and there is a risk of further brain damage.Early recognition and treatment of biochemical disturbances is essential for optimal management and satisfactory long-term outcome.Seizures represent the signal of neurological disease in the newborn period and these convulsive phenomena are the most frequent manifestation of neonatal neurological disorder 1 .Delay in recognition and treatment results in poor neurological outcome 2 .Seizures during the neonatal period are relatively common, occurring in 1.8 to 3.5 per 1000 live births, with greater frequency in premature or low birth weight babies as compared to term babies 3 .Neonatal seizures are always due to an underlying cerebral or biochemical abnormalities although no cause may be identified in 10% of cases 4 .In the Neonatal Intensive Care Unit, the incidence goes as high as 10-25% out of which about 15% will die and 35 to 40% will have major neurological sequelae 5 .There is increasing evidence that neonatal seizures have an adverse effect on neurodevelopment and may predispose to cognitive, behavioural or epileptic complication later in life 6 .The present study was conducted to evaluate the incidence, etiological factor, clinical types and to observe various biochemical abnormalities.

Materials and Methods:
The present study was a retrospective, observational study conducted in the Neonatal Intensive Care Unit and Nursery at B. P. Koirala Institute of Health Sciences from 1 st December 2006 to 15 th October 2007.All neonates with seizure before 28 days of life were included in the study.The neonatal seizures were classified according to Volpe's classification into subtle, focal clonic, multifocal clonic, tonic and myoclonic.Metabolic abnormalities and infections were noted.Hypoglycemia were defined as blood sugar < 40 mg/dl, and hypocalcaemia when total serum calcium was less than 7.0 mg/dl.Total 90 cases of neonatal seizure presenting before 28 days of life was included in the study.Age, sex, etiological factors and biochemical parameters were recorded in a predesigned data sheet.The data was analysed by using SPSS 10.0 version.

Results:
Total admission during the study period was 867 live births, out of which 90 neonates presented with seizure.The incidence of neonatal seizure was 10.3/ 1000 live births.The seizures were more common in male babies observed in our study.65 (72.2%)neonates were born to multiparous women while 35 (38%) were born to primigravidas.In birth asphyxia (n= 40), the most common type of seizure observed was subtle seizure 20 (50%), followed by focal clonic 10 (25%) and multifocal clonic 5 (12.5%).Tonic type of seizure was observed in 3 (7.5%)and myoclonic in 2 (5%).Meningitis and septicaemia was the second most common cause of neonatal seizure observed in our study.Among metabolic abnormalities hypoglycaemia was found in 20 (22%) and hypocalcaemia in 10 (11%).The commonest cause of seizure was birth asphyxia presenting within 72 hours.Among infection septicaemia and meningitis was the most common infection leading to neonatal seizure.Among biochemical abnormalities the most common cause of seizure observed in our study was hypoglycaemia and hypocalcaemia.Subtle seizures were the commonest type of seizure observed in this study.In majority of cases the seizure occurred within 24 hours that has been shown in Table III.

Discussion:
Neonatal seizure is an important cause of neonatal morbidity and mortality.The present study showed incidence of 10.3/ 1000 live births which is similar to Holden KR et al study 7 .In the present study the most common type of seizure observed were subtle which constitutes 50% of seizure in both term and preterm babies 8 .The most common cause of seizure encountered in this study was birth asphyxia, which is comparable with Sood A et al study that reported 45.7% cases of seizure were due to birth asphyxia 9 .Our study showed 20% of the seizure were due to infections i.e. septicaemia and meningitis, which is also similar to study, conducted by Ledigo hypoglycaemia and hypocalcaemia was the commonest cause for neonatal seizure.Subtle seizure was the commonest type of seizure that can be easily missed, as it is very mild.

Table 1 :
Incidence of Neonatal Seizure According to Weight.