Controversies regarding neonatal seizure recognition

Recognition and classification of neonatal seizures remain problematic, particularly when clinicians rely only on clinical criteria. Physicians should utilize synchronized video-EEG-polygraphic recordings to correlate suspicious behaviors with electrographic seizures, to help limit misdiagnosis and overtreatment of either normal or abnormal nonepileptic behaviors. Since neonatal seizures, particularly status epilepticus, predict an increased risk for later epilepsy and other neurological sequelae, accurate diagnoses are needed for aggressive antiepileptic drug use in the NICU, as well as family counseling and anticipatory medical care after discharge. Neurophysiological documentation of neonatal seizures also must be integrated with an appreciation of pathophysiological mechanisms responsible for brain lesions that cause seizures. Maternal-fetal-placental diseases, as well as genetic vulnerabilities may be responsible for seizures long before diagnosis in the newborn period. Alternatively, the severity of seizures in neonates with perinatal asphyxia or other etiologies may be independently associated with brain injury.

Seizures in the newborn are one of the few, neonatal neurological emergencies. While prompt diagnostic and therapeutic plans are necessary, unresolved medical issues continue to challenge the physician's evaluation of the newborn with suspected seizures (table I) [1-3]. Recognition of the seizure state remains the foremost challenge to overcome. Clinical and electroencephalographic manifestations of neonatal seizures vary dramatically from those of older children. This generalization is underscored by the brevity and subtlety of the clinical repertoire of the newborn's neurological examination. Environmental restrictions surrounding the sick infant in an intensive care setting, including confinement within an isolette, intubation and attachment to multiple catheters limit accessibility. Medication alters arousal and muscle tone, which further limit the clinician's ability to consider these clinical neurological signs as surrogate markers of underlying brain disorders. Brain injury from antepartum factors may later be expressed as neonatal seizures, as part of a postnatal, encephalopathic clinical picture which may only be precipitated by stress during the intrapartum and neonatal periods [4]. Alternatively, medical conditions during parturition or after birth may cause seizures, with coincident injury. For medication options to effectively treat seizures, new agents need to be designed for specific etiologies, timing of injury, and the unique cellular/molecular organization of the immature brain.

This review addresses the challenges and controversies regarding neonatal seizure recognition in the context of current clinical practices. Experimental models of neonatal seizures elucidate the pathophysiological mechanisms and adverse consequences of seizures on brain development. Since 20% to 50% of children with neonatal seizures experience later epilepsy, diagnostic accuracy is essential [5, 6], particularly for the newborn who suffers a prolonged seizure state.