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Chapter 19 Alterations of Neurologic Function in Children Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. Embryonic Development of the Neural System Dorsal (posterior) induction Ventral (anterior) induction Proliferation Migration Organization Myelination Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 2 Structure and Function of the Nervous System in Children Develops from a dorsal thickening of the ectoderm (neural plate) Neural groove and folds Neural tube Neural crest Mesoderm Blood vessels, microglial cells, dural and arachnoid layers of the meninges, the capsule of some peripheral nerve endings, and nerve coverings Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Structure and Function of the Nervous System in Children Sulcus limitans Basal plate Alar plate Sutures Fontanels Myelin sheath A lipid-protein sheath Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Structure and Function of the Nervous System in Children Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Structure and Function of the Nervous System in Children Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Neural Tube Defects (NTD) Caused by an arrest of the normal development of the brain and spinal cord Occurs in about 3000 U.S. pregnancies/yr Strong association of fetal death Reduces the actual prevalence of neural defects at birth Maternal folate deficiency Periconceptional supplementation with folic acid can reduce NTD by up to 70% Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Structural Malformations Defects of neural tube closure Anencephaly Encephalocele Meningocele Myelomeningocele • Arnold-Chiari type II malformation • Tethered cord syndrome Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Structural Malformations Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Axial Skeleton Malformations Spina bifida occulta Vertebral defect that allows the protrusion of the neural tube contents Cranial deformities Acrania Craniosynostosis Microcephaly Congenital hydrocephalus • Macewen sign (“cracked pot” sign) Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Encephalopathies Static encephalopathies Cerebral palsy: a diverse group of nonprogressive syndromes that affect the brain and cause motor dysfunction beginning in early infancy • Static cerebral palsy • Dyskinetic cerebral palsy • Ataxic cerebral palsy Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11 Inherited Metabolic Disorders of the Central Nervous System Defects in amino acid metabolism Phenylketonuria (PKU) • Hyperphenylalaninemia Defects in lipid metabolism Lysosomal storage diseases Tay-Sachs disease Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Seizure Disorders Epilepsy Partial seizures Generalized seizures Unclassified epileptic seizures • Infantile spasms • Lennox-Gastaut syndrome • Juvenile myoclonic epilepsy Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Benign Febrile Seizures Occur in 2% to 5% of children Brief and self-limited Often between ages 6 months and 5 years Peak incidence at 14 to 18 months Pathogenesis unknown Influencing factors: age, degree and rate of temperature elevation, nature of illness Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Status Epilepticus Continuing or recurring seizure activity Recovery from seizure activity is incomplete Seizure activity is unrelenting • Usually lasts for 30+ minutes • Any seizure activity can evolve into status epilepticus Status epilepticus is a medical emergency that requires immediate intervention Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Acute Encephalopathies Reye syndrome Usually associated with influenza B or varicella virus infections in children who have taken aspirin Pathology unknown Inborn errors of metabolism are a contributing factor Profound hypoglycemia, hypoketonemia, hyperammonemia, increase in serum short-chain fatty acids Liver shows diffuse deposits of lipids and absence of any inflammatory reaction or necrosis Fatty degeneration of the kidneys leads to azotemia (excess urea in the blood) Brain is extremely edematous Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Acute Encephalopathies Meningitis Inflammation of the meningeal coverings of the brain and spinal cord • Bacterial meningitis 6000 cases per year; half in children younger than 18 • Viral meningitis Hallmark of viral meningitis or aseptic meningitis is a mononuclear response in the CSF and the presence of normal blood glucose level Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Children and HIV HIV infections in children Perinatally through the placenta Exposure to infected maternal blood and vaginal secretions Postpartum ingestion of breast milk Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Cerebrovascular Disease Cerebrovascular disease in children differs in adults in three ways Absence of predisposing factors Differences in the clinical response Anatomic site of the pathologic condition Occlusive cerebrovascular disease Hemorrhagic cerebrovascular disease Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Childhood Tumors Most common solid tumor and second most common primary neoplasm ~50% of solid tumors are nonmalignant Account for 20% of all childhood cancers Primary is leukemia Annual incidence of 2.4 to 4 per 100,000 2000 cases are diagnosed each year The leading cause of death from disease in children 1 to 15 years Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Childhood Tumors Brain tumors Medulloblastoma Ependymoma Astrocytoma Brainstem glioma Optic nerve glioma Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 Childhood Brain Tumors Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Childhood Tumors Embryonal tumors Neuroblastoma (aggressive tumor) • Originates in neural crest cells (develop into sympathetic • • • • nervous system) Most diagnosed during first 2 years 75% found before child is 5 years Abdomen (65%) most often in the adrenal medulla Mediastinum (15%) Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Childhood Tumors Embryonal tumors Retinoblastoma (rare congenital eye tumor) Rarely diagnosed after age 5 40% inherited as autosomal dominant disorder Prognosis for most children is excellent, with a greater than 90% long-term survival • Children with bilateral or metastatic disease have a poor prognosis • About 75% have useful vision in the treated eye Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Childhood Tumors Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25
