[Neonatal convulsions: influence of the electroencephalographic pattern and the response to treatment on the outcome]

Neonatal convulsions continues being motive for multiple controversies: the diagnosis only by clinical approaches, the necessity to confirm with EEG record and their treatment and control.

To establish the incidence of type of clinical neonatal seizures and the correspondence of these to the EEG trace background and the EEG epileptic activity, the underlying etiology, the response to antiepileptic treatment, and their prognosis.

Retrospective study of admitted newborns with the diagnosis of neonatal seizures in our hospital, during the period included between January 1993 and October 2001. Some of variables collected were: birth and gestational age, Apgar, clinical pattern, duration of the convulsions, critical and intercritical EEG traced, EEG background, etiological diagnosis, treatment used and response of the same, evolution and neurological state at hospital discharge and at one year of age (corrected age in preterm infants).

74 children were admitted with neonatal convulsion diagnosis, of these only 56 EEG convulsions were confirmed (42% presented subtle seizures, 33.9% tonic, 64.3% clonic multifocal, 10.7% clonic focal, and 16.1% myoclonic multifocal). 55.4% of the infants had 2 or more types of clinical convulsions, 25% of all had an epileptic state, and 42.9% had at some time of the EEG record, electroclinical dissociation. The more frequent critical EEGs abnormalities was multifocal discharges (64.3%), and together with the focal discharges of low frequency had significant (p<0.01) worse pharmacological control, and also unfavourable outcome. The infants having had EEGs background moderately and markedly abnormal showed unfavourable outcome in 72.2% and 100% respectively, while it was only in 15.4% of the infants who had EEGs background normal or lightly abnormal. With the antiepileptic treatment the clinical control of the convulsions was obtained in more than 80% of the cases, while control of the electrical convulsions was only in 62.5%. There was a higher significant association between favourable response to treatment and normal neurological examination at hospital discharge and at 1 year of age.

The necessity to confirm by means of EEG record the neonatal clinical convulsions, before and after having established the anticonvulsant treatment, due to the control of electrical convulsions improves their neurological outcome.