[Convulsions in neonates. Clinical, electrographic, etiopathogenic and prognostic aspects]. / Convulsions du nouveau-ne. Aspects clinique, electrographique, etiopathogenique et pronostique.

ABSTRACT

121 cases of neonatal convulsions, including 79 cases of status epilepticus and 42 cases of isolated convulsions are studied. The great number of premature infants (40/121 newborns born before a gestational age of 37 weeks) must be pointed out. The clinical symptoms and EEG activity occurring during the first 24 hours following the onset of convulsions are analysed. Their descriptions confirm previous ones. Comparison of the populations of preterm and term infants demonstrates that the pre- and post-ictal neurological states are equally severe in both groups and that there is no difference between groups in the more or less precocious onset of convulsions. The value of the interictal EEG already described in status epilepticus of terms infants as predicting a poor prognosis, is confirmed. In addition, the very poor prognosis of an abnormal EEG pattern of the premature newborn, i.e. an EEG lacking any pattern corresponding to any gestational age, is demonstrated. Such EEGs of very poor prognosis have been detected in 46 cases. They reveal the degree of severity of the cerebral lesions, EEG abnormalities and cerebral lesions varying with gestational age. This study confirms the relatively mild severity of isolated convulsions as compared to status epilepticus. It demonstrates the severity of convulsions in premature newborns and of the electrographical discharges without simultaneous clinical event. The prognostic value of the absence or presence of a sleep cycle as early as the 24 hours following the onset of convulsions must be noted. Most of the neonatal convulsions are secondary to birth hypoxia or asphyxia and to meningo-encephalitis. In this study the small number of seizures due to metabolic factors is striking and contrasts with their great frequency in other series. The cause of the seizures is unknown in 12% of the cases; some of these cases of unknown origin correspond to the description of the 'convulsions of the 5th day'. The prognosis in full-term newborns has been improved greatly in recent years, probably due to improvement in obstetrical and neonatal intensive care.