Alterations of Neurologic Function in
Children
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Dorsal (posterior) induction

Ventral (anterior) induction

Proliferation

Migration

Organization

Myelination
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
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
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
Sulcus limitans

Basal plate

Alar plate

Sutures

Fontanels

Myelin sheath
 A lipid-protein sheath
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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
 Reduces the actual prevalence of neural defects at birth
Maternal folate deficiency
 Periconceptional supplementation with folic acid can reduce NTD by up to 70%
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
Defects of neural tube closure
 Anencephaly
 Encephalocele
 Meningocele
 Myelomeningocele
•
Arnold-Chiari type II malformation
•
Tethered cord syndrome
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

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)
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
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
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
Defects in amino acid metabolism
 Phenylketonuria (PKU)
•
Hyperphenylalaninemia

Defects in lipid metabolism
 Lysosomal storage diseases
 Tay-Sachs disease
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
Epilepsy
 Partial seizures
 Generalized seizures
 Unclassified epileptic seizures
•
Infantile spasms
•
Lennox-Gastaut syndrome
•
Juvenile myoclonic epilepsy
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
Occur in 2% to 5% of children

Brief and self-limited
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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
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
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
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
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
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
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
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
HIV infections in children
 Perinatally through the placenta
 Exposure to infected maternal blood and vaginal secretions
 Postpartum ingestion of breast milk
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
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
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
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Most common solid tumor and second most common primary neoplasm
 Primary is leukemia
~50% of solid tumors are nonmalignant
Account for 20% of all childhood cancers
 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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
Brain tumors
 Medulloblastoma
 Ependymoma
 Astrocytoma
 Brainstem glioma
 Optic nerve glioma
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
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%)
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
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
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