Transcript Chapter_019 - IHMC Public Cmaps (2)

Chapter 19
Alterations of Neurologic Function in
Children
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Embryonic Development of the
Neural System
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Dorsal (posterior) induction
Ventral (anterior) induction
Proliferation
Migration
Organization
Myelination
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Structure and Function of the
Nervous System in Children
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Develops from a dorsal thickening of the
ectoderm (neural plate)
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Neural groove and folds
Neural tube
Neural crest
Mesoderm
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Blood vessels, microglial cells, dural and
arachnoid layers of the meninges, the capsule of
some peripheral nerve endings, and nerve
coverings
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Structure and Function of the
Nervous System in Children
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Sulcus limitans
Basal plate
Alar plate
Sutures
Fontanels
Myelin sheath
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A lipid-protein sheath
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Structure and Function of the
Nervous System in Children
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Structure and Function of the
Nervous System in Children
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Neural Tube Defects (NTD)
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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
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Reduces the actual prevalence of neural defects
at birth
Maternal folate deficiency
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Periconceptional supplementation with folic acid
can reduce NTD by up to 70%
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Structural Malformations
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Defects of neural tube closure
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Anencephaly
Encephalocele
Meningocele
Myelomeningocele
• Arnold-Chiari type II malformation
• Tethered cord syndrome
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Structural Malformations
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Axial Skeleton Malformations
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Spina bifida occulta
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Vertebral defect that allows the protrusion of the
neural tube contents
Cranial deformities
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Acrania
Craniosynostosis
Microcephaly
Congenital hydrocephalus
• Macewen sign (“cracked pot” sign)
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Encephalopathies
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Static encephalopathies
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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
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Inherited Metabolic Disorders of
the Central Nervous System
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Defects in amino acid metabolism
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Phenylketonuria (PKU)
• Hyperphenylalaninemia
Defects in lipid metabolism
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Lysosomal storage diseases
Tay-Sachs disease
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Seizure Disorders
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Epilepsy
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Partial seizures
Generalized seizures
Unclassified epileptic seizures
• Infantile spasms
• Lennox-Gastaut syndrome
• Juvenile myoclonic epilepsy
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Benign Febrile Seizures
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Occur in 2% to 5% of children
Brief and self-limited
Often between ages 6 months and 5 years
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Peak incidence at 14 to 18 months
Pathogenesis unknown
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Influencing factors: age, degree and rate of
temperature elevation, nature of illness
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Status Epilepticus
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Continuing or recurring seizure activity
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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
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Acute Encephalopathies
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Reye syndrome
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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
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Acute Encephalopathies
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Meningitis
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Inflammation of the meningeal coverings of the
brain and spinal cord
• Bacterial meningitis
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6000 cases per year; half in children younger than 18
• Viral meningitis
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Hallmark of viral meningitis or aseptic meningitis is a
mononuclear response in the CSF and the presence of
normal blood glucose level
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Children and HIV
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HIV infections in children
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Perinatally through the placenta
Exposure to infected maternal blood and vaginal
secretions
Postpartum ingestion of breast milk
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Cerebrovascular Disease
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Cerebrovascular disease in children differs in
adults in three ways
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Absence of predisposing factors
Differences in the clinical response
Anatomic site of the pathologic condition
Occlusive cerebrovascular disease
Hemorrhagic cerebrovascular disease
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Childhood Tumors
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Most common solid tumor and second most
common primary neoplasm
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~50% of solid tumors are nonmalignant
Account for 20% of all childhood cancers
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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
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Childhood Tumors
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Brain tumors
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Medulloblastoma
Ependymoma
Astrocytoma
Brainstem glioma
Optic nerve glioma
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Childhood Brain Tumors
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Childhood Tumors
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Embryonal tumors
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Neuroblastoma (aggressive tumor)
• Originates in neural crest cells (develop into sympathetic
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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%)
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Childhood Tumors
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Embryonal tumors
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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
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Childhood Tumors
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