Chapter 18: Alterations of Neurologic Function in Children

The nervous system develops in coordinated stages beginning around day 40 of gestation with neural tube closure, followed by progressive neuronal migration, synaptogenesis, and myelination that continues into early childhood. Disruption during these critical developmental windows can result in permanent neurologic impairment, exemplified by alcohol-related neurodevelopmental disorder from in utero exposure. Structural malformations such as neural tube defects represent major contributors to childhood mortality and morbidity, including anencephaly, encephalocele, meningocele, myelomeningocele, and spina bifida occulta, with folic acid deficiency and maternal metabolic conditions serving as key preventable risk factors. Associated complications such as Chiari II malformation, hydrocephalus, and tethered spinal cord frequently accompany myelomeningocele. Other developmental malformations including craniosynostosis, microcephaly, megalencephaly, and cortical dysplasias impair normal brain growth and function. Congenital hydrocephalus arises from excess cerebrospinal fluid production, obstruction, or impaired reabsorption, presenting with characteristic clinical signs. Cerebral palsy, the most common nonprogressive encephalopathy in childhood, results from prenatal or perinatal brain injury and manifests in spastic, dystonic, and ataxic presentations with significant motor and cognitive sequelae. Progressive encephalopathies such as inherited metabolic disorders, including phenylketonuria and lysosomal storage diseases, cause neurodegeneration when untreated. Infections including bacterial meningitis from characteristic organisms and viral encephalitis remain serious threats to neurologic development. Perinatal and childhood strokes, influenced by conditions like sickle cell disease and arteriovenous malformations, contribute to significant morbidity. Seizure disorders affect a substantial proportion of the pediatric population, with febrile seizures being most prevalent. Childhood brain tumors, particularly astrocytomas and medulloblastomas, represent leading causes of cancer mortality in children, while neuroblastoma and retinoblastoma demonstrate the impact of genetic mutations on neural crest-derived tissues.