Neonatal seizures.

Epileptic seizures are more frequent in the neonate than at any other time. The incidence of neonatal seizures (NNS) is estimated to be between 1.5 and 5.5/1000 living births, its onset being during the first week in 80% of cases. Mortality rate remains very high (20-45%). Not all paroxysmal manifestations are epileptic, and differential diagnosis remains an important challenge. Neonates may present with different types of seizures: clonic, tonic, myoclonic (axial, focal, erratic), epileptic spasms, and subtle seizures, including autonomic signs or automatisms. The main etiology is hypoxic-ischemic encephalopathy (40-45%) with a very early onset, and variable semiology including all seizure types. An EEG is necessary to recognize the seizures, and interictal tracing may help in assessing prognosis. Ischemic stroke is associated with seizures of early onset, being focal or unilateral. Interictal EEG is asymmetrical, with focal or unilateral patterns. Other etiologies less often linked to epileptic seizures must be looked for such as brain infection, metabolic disorders, chromosomal abnormalities, inborn errors of metabolism, brain malformations, and vitamin B6 dependency. Neonatal epilepsy syndromes may have favorable (benign familial neonatal seizures) or poor (early infantile encephalopathy with epilepsy, early myoclonic encephalopathy, and migrating partial seizures in infancy) prognosis.