TY - CHAP M1 - Book, Section TI - Neonatal Seizures A1 - Malcolm, William F. PY - 2015 T2 - Beyond the NICU: Comprehensive Care of the High-Risk Infant AB - DefinitionA clinical seizure is defined as a paroxysmal alteration of neurologic function (behavioral, motor and/or autonomic).An electrographic seizure is defined as a repetitive discharge that evolves in time and space. In practical terms, it is a seizure detected only by electroencephalogram (EEG) without clinical correlate.An electroclinical seizure is an event with concomitant clinical and electrographic seizures.IncidenceThe incidence of seizures in the term neonate ranges between 1 and 3/1000 live births.Higher incidence is observed among neonates with low gestational age and low birthweight—up to 57.5/1000 for infants <1500 g and 20.4/1000 for infants <28 weeks.The neonatal period has the highest incidence of seizures across the life span.PathophysiologyThe immature brain is highly excitable.The balance between excitation and inhibition favors excitation.The neurotransmitter receptors are developmentally regulated with lower expression of inhibitory receptors (some γ-aminobutyric-acid or GABA receptors) and higher expression of excitatory receptors (glutamate receptors) compared to adulthood.GABAA receptor activation in the immature brain can cause depolarization instead of hyperpolarization because the chloride gradient is reversed in the immature brain.Developmental regulation of ion channels and neuropeptides may also contribute to neuroexcitation.The neonatal brain is a unique environment that likely explains, at least in part, the refractoriness to common antiepileptic medications.EtiologySee Table 39-1.Etiology based on seizure onsetFirst 6 hours after birthNKH, sulfite oxidase/molybdenum cofactor deficiency, B6/PLP dependent seizures, cortical dysplasia, trauma, local anesthetic toxicityAfter first 6 hoursHIE, cortical dysplasias, vascular, trauma, infectious, metabolic, toxicRisk factorsFamily history of neonatal seizuresBenign familial neonatal seizures (BFN): KCNQ1, KCNQ2, KCNQ3 (Note: Some mutations can be associated with a malignant course, and not benign as previously thought.)Sodium channelopathies: SCN1A, SCN2AMetabolic disordersProblems with pregnancyFever and/or rash during pregnancyCongenital infection (SCRATCHES: syphilis, CMV, rubella, AIDS, toxoplasmosis, chicken pox, HSV, enterovirus)ChorioamnionitisHistory of vaginal bleedingAbruption, previaHiccups/increased fetal movementNKH (nonketotic hyperglycinemia), B6/PLP (vitamin B6/pyridoxal-5-phosphate) dependent seizures, cortical dysplasiaSubstance abuseCocaineHELLP syndromeFatty acid oxidation disordersProblems with deliveryFetal heart rate abnormalities, prolapsed cord, placenta abruption, previaHypoxic-ischemic encephalopathy (HIE)No maternal pain relieve, pupillary abnormalities, cardiac arrhythmiaLocal anesthetic toxicityPrecipitous delivery, vacuum, breechSubdural, subarachnoid and intraparenchymal hemorrhages, strokeNo vitamin K administration at birthHemorrhagic disease of the newbornMaternal fever and abnormal amniotic fluidChorioamnionitisPremature delivery/extremely low birthweight infantsHigher risk of intraventricular hemorrhage (IVH), sepsis, and meningitisClinical presentationClinical assessment of a suspected seizure (paroxysmal alteration of neurologic function) should includeMental status: Most seizures course with altered mental status.Spontaneous character of the event: Seizures are characteristically unprovoked and should not respond to restrain, change in position or stimulation.Vital signs: Most seizures occur with tachycardia.Clinical seizures typesSubtle seizuresParoxysmal alterations in neonatal behavior and motor or autonomic function (tachycardia, blood pressure elevation, apnea, cutaneous vasomotor phenomena, pupillary change, salivation, or drooling) that are not clearly tonic, clonic, or myoclonic.Sustained eye opening with ocular fixation or horizontal gaze deviation appear to be the most common manifestation in preterm and term neonates, respectively.Chewing, pedaling motions, and autonomic phenomena can also be seen.Isolated apnea is an uncommon seizure manifestation but it may represent a seizure when associated with other symptoms such as ocular phenomena or mouth movements. The more common association with tachycardia rather than bradycardia helps in the differential with ... SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1105545550 ER -