Page 52 - ILAE_Lectures_2015

Chapter 6

Neonatal seizures

RONIT M. PRESSLER

Department of Clinical Neurophysiology, Great Ormond Street Hospital, London

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Introduction

The immature brain seems more prone to seizures than the more mature brain. Seizures are
more common in the neonatal period than during any other time throughout life. Seizures in
the neonatal period are also the most common neurological emergency and are associated with
high mortality and morbidity1,2.

The incidence of seizures in infants born at term is 0.53 per 1000 live births; the incidence is
even higher in preterm infants, ranging from 113% of very low birthweight infants3.
Variations of described numbers of incidence can be explained by different diagnostic
definitions and methods used. Most of these epidemiological studies include only clinical
seizures. The exact incidence of electrographic, clinically silent seizures is as yet unknown.
The majority of neonatal seizures occur on the first day, and 70% of all cases eventually
recognised have been diagnosed by the fourth day.

Aetiology

In contrast to seizures in infancy and childhood, most neonatal seizures are acute and
symptomatic with suspected specific causes; relatively few seizures are idiopathic or part of a

Table 1. Causes of neonatal seizures3-5.

Cause Frequency

Hypoxic-ischaemic encephalopathy 3053%
717%
Intracranial haemorrhage 617%
317%
Cerebral infarction 214%

Cerebral malformations 0.15%
422%
Meningitis/septicaemia
34%
Metabolic
Hypoglycaemia 1%
4%
Hypocalcaemia, hypomagnesaemia 2%
1%
Hypo-/hypernatraemia
Inborn errors of metabolism (such as pyridoxine dependency, folinic acid-
responsive seizures, glucose transporter defect, non-ketotic
hyperglycinaemia, propionic aciduria)
Kernicterus
Maternal drug withdrawal
Idiopathic
Benign idiopathic neonatal seizures
Neonatal epileptic syndromes
Congenital infections