Update of neonatal seizures

Seizures are the most distinctive manifestation of neurologic dysfunction in the newborn infant. In earlier reports, seizures occurred in 3/1000 full-term infants and up to 60/1000 premature infants.This essay was constructed to do a comprehensive review on update of neonatal seizure regarding pathophysiology, etiology, clinical picture and update on investigations and management.The mechanisms of seizures in newborns are complex and not well-understood. As a result, theories of epileptogenesis are rapidly evolving.The basic mechanism of neuronal excitability is the action potential, a hyperexctiable state can result from increased excitatory synaptic neurotransmission, decreased inhibitory neurotransmission, an alteration in voltage-gated ion channels, or an alteration of intra- or extra-cellular ion concentrations in favor of membrane depolarization.Neurotransmitters are substances that are released by the presynaptic nerve terminal at a synapse and subsequently bind to specific postsynaptic receptors. The major neurotransmitters in the brain are glutamate, Gamma-Amino-Burtyric Acid (GABA), Acetylcholine (Ach), norepinehprine, dopamine, serotonin, and histamine. Other molecules, such as neuropeptides and hormones, play modulatory roles that modify neurotransmission over longer time periods.Classification of neonatal seizures based on electroclinical finding is:• Clinical seizures with coincident electrocortical signature:- Focal clonic.- Focal tonic.- Myoclonic.- Spasms.• Clinical seizures without a consistent electrocortical signature:- Myoclonic.- Generalized tonic.- Motor automatisms.• Electrical seizures without clinical seizure activity.The major etiologies of neonatal seizures in relation to seizure onset and relative frequency is hypoxic-ischemic and intracranial hemorrhage. Intracranial infection developmental defect, hypoglycemia, hypocalcemia and other metabolic disturbances and epileptic syndrome.The most common cause of neonatal convulsion was HIE which was predominant in full-term, followed by ICH which was predominant in preterm, then CNS infection, metabolic disturbances and CNS malformation.Diagnosis depends mainly on clinical manifestations and investigations.Cranial ultrasonography, CT, EEG and laboratory data including electrolytes such as serum glucose, serum calcium, serum magnesium and CSF analysis play an important role in diagnosis of neonatal convulsions.Cranial ultrasound is more sensitive than CT in detecting hypoxic ischemic encephalopathy, while CT is superior in detecting subarachnoid and subdural hemorrhage and both investigator tools show the same sensitivity in detecting other type of hemorrhage, CNS infection and congenital brain anomalies.It is a valuable tool to quickly ascertain intracranial hemorrhage, particularly intraventricular hemorrhage, has occurred in the premature infant. It is an excellent method for monitoring the progression or resolution of the pathologic process.It is a very useful tool in the identification of focal infarction and hemorrhagic lesions in the term or near term infant as well as congenital midline anomalies, cystic lesions, vascular malformations and intracranial calcifications, and in the definition of extra-axial fluid collections.Cranial CT scan is a much more sensitive tool than ultrasound in detecting parenchymal abnormalities. The disadvantage is that the sick neonate must be transported to the imaging site. A distinct advantage is that with modern CT techniques, a study can be obtained in approximately 10 minutes.Cranial MRI is the most sensitive test in determining the etiology of neonatal seizures, particularly when electrolyte imbalance has been excluded as a cause for seizures.EEG plays a vital role in properly identifying and differentiating neonatal seizures from non-epileptic events. EEG is the optimum method to identify, classify, and quantify neonatal seizures. An electrographic diagnosis for neonatal seizures provides a better-defined start and endpoint for identification.One of the great advantages of CFM is its simplicity and the possibility of quick online interpretation and analysis of overall brain function. The treatment of seizures depends on the treatment of the cause such as correcting the electrolyte and hypoglycemia. Phenobarbital is the first line treatment option with phenytoin being the second line drug of choice.Monotherapy is the preferred method of seizure control because it decreases the chance of drug interactions and side effects.A second anticonvulsant agent can be added if seizures persist. There are new drugs such as topiramate and other choices under test as botinamide and lidocaine and palraldehyde were used for cases not responding to treatment. There is increasing evidence that neonatal seizures have an adverse effect on neurodevelopmental outcome and predispose to cognitive, behavioural or epileptic complications in later life.