The Massachusetts General Hospital Handbook of Neurology

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Child Neurology > Development

Development

A. History

Problems or drug use in pregnancy, weeks gestation, Apgars, birth weight, postnatal problems, developmental milestones (see Table 37), school performance. For adolescents, try to ask about drugs and sexual activity with parents out of the room.

B. General exam

Head circumference (see Figure 17, p. 139), eye exam, face and limb morphology, skin (caf -au-lait, ashleaf, palmar creases), and cardiovascular exam. In infants, fontanelles (see p. 137), skull, and base of the spine.

C. Neurological exam

see primitive reflexes and developmental milestones, below.

• Infants: Alertness, posture, spontaneous movements, cry pitch and volume, pupil responses, ability to track a face, orientation towards noise, reflexes (see Table 36), response to pinch. Assess tone (premature infants are normally hypotonic).

  • Supine:

    • Hypertonic: Arched back, more than a few beats of clonus, asymmetric tonic neck reflex that is obligate or present after age 6 mo, and inability to dorsiflex the foot to the shin in infants <6 mo.

    • Hypotonic: Frog-legged, little spontaneous movement.

  • Traction response: Pull the infant from supine to sitting.

    • Hypertonic: Persistent leg extension.

    • Hypotonic: Head lag, no compensatory leg flexion.

  • Horizontal suspension:

    • Hypertonic: Back extension.

    • Hypotonic: Infant drapes over your hands.

  • Vertical suspension: Hold baby under armpits.

    • Hypertonic: Scissoring of legs with plantar ankle flexion.

    • Hypotonic: Head droops; baby slips through your fingers.

• Older children: Toddlers may be examined better on a parent's lap. Use toys to engage them; watch movement during spontaneous play.

D. Normal patterns of myelination

In general, myelination progresses caudal to rostral, central to peripheral, and dorsal to ventral. Because there is no gray-white differentiation in infants, it is easy to miss small amounts of edema.

• Imaging: Use T1 MRI for the first 4 mo of life, T2 thereafter.

• At birth: Central cerebellar white matter, superior and inferior cerebellar peduncles, brainstem, and thalamus.

• By 1 month: Corticospinal tracts, pre- and postcentral gyri, optic nerves and tracts.

• By 3 months: Middle cerebellar peduncles, optic radiations, and posterior limb of the internal capsule.

• By 8 months: Anterior limb of the internal capsule, corpus callosum, centrum semiovale, and subcortical U-fibers.

• By 18 months: Nearly adult appearance except for the peritrigonal region posterior to the occipital horns.

• By 20 years: Peritrigonal region is myelinated.

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E. Normal reflexes and milestones

F. Progressive developmental delay or regression

• H&P: Ask about progression ( Are there things your child could do before but can't do now? ), CNS trauma, family history, consanguinity, child abuse or neglect. Perform a good general exam as well as neurological exam and head circumference.

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G. Intelligence quotient (IQ)

Average = 100; with 15 points for each standard deviation from the mean.

• Causes: Consider hydrocephalus, tumors, autism, epilepsy, infections, toxins, abuse, and metabolic disorders.

  • Gray matter dz: Cerebral cortex dz cognitive loss, seizures. Basal ganglia dz movement disorders, cerebellar dz ataxia. Causes include tumors, severe epilepsy, lysosomal disorders, ceroid lipofuscinosis, autism spectrum, aminoacidopathy.

  • White matter dz: Corticospinal sx, blindness, and other focal deficits, but seizures rare. Causes include progressive hydrocephalus, childhood multiple sclerosis, leukodystrophies, Alexander's dz, Canavan's dz, galactosemia, Pelizaeus- Merzbacher dz.

  • Peripheral as well as central nervous system dz? Suggests lysosomal storage disorders; mitochondrial disorders.

  • Other organs involved besides nervous system? Look especially at skin, eyes, viscera (murmurs, hepatomegaly), dysmorphic features, growth failure. Suggests aminoacidurias (p. 143), neurocutaneous syndromes (p. 146), chronic infections, e.g., TORCH (see p. 142), hypothyroidism, chronic toxin exposure.

• Tests:

  • Blood: Electrolytes, CBC, lactate, liver function tests, lead level.

  • Neuroimaging: Look for hydrocephalus, focal lesions, atrophy, diffuse white matter change. Compare with normal progression of myelination, above.

  • Other: Consider metabolic screen (p. 142), LP (p. 224).

H. Static developmental delay

• Tests: First, MRI. Evaluate structural lesions; if none are found, consider further metabolic workup. Pts with global developmental delay should have tests for fragile X, Rett syndrome, and others if appropriate. Any patient with language delay should always have hearing formally tested.

• DDx: Slowly progressive congenital disorders.

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• Cerebral palsy: Generic name for static encephalopathy, usually from prenatal rather than perinatal factors. Classified by motor findings.

  • Spastic hemiplegia (arm and leg): Usually from developmental malformation or stroke. Usually normal intelligence, sometimes seizures.

  • Spastic diplegia (legs >> arms): Usually from prematurity. Intelligence may be near normal; seizures rare. May need orthopedic rx of spasticity.

  • Spastic quadriplegia: Usually from severe diffuse brain injury. Severe seizures and mental retardation are common.

  • Athetoid: From hypoxia, cerebellar or basal ganglia lesions, kernicterus (severe neonatal jaundice).

• Perinatal events:

  • H&P: Maternal risk factors and delivery. Poor alertness, periodic breathing, hypotonia, seizures. Bulging fontanelles and signs of high ICP in severe hemorrhage.

  • Term newborns:

  • Hypoxic-ischemic encephalopathy (HIE): Defined as cord blood gas pH <7, Apgar 0-3 at >5 min, neuro sx (seizures, coma, hypotonia), and other organ involvement.

    • Acute total asphyxia: Injures thalamus and brainstem more.

    • Prolonged partial asphyxia: Injures cerebral cortex and white matter more.

    • Prognosis: Alertness may improve between 12-24 h of age, then worsen over the next 72 h. Severe HIE causes mental retardation, spastic quadriparesis, and seizures, but mild HIE resolves within 2 d without sequelae.

  • Other: Stroke, CNS bleed, etc.

• Premature infants:

  • Periventricular leukomalacia (PVL): Presumed to be from HIE. In premature newborns, this mostly affects subcortical white matter, causing spastic diplegia, quadriplegia, or visual impairment. Severe HIE also causes mental retardation and microcephaly. PVL can be shown, after 1-2 wk, with CT or MRI.

  • Periventricular-intraventricular hemorrhage (PIVH): A germinal matrix hemorrhage, probably the effect of transient hypertension on vessels previously weakened by ischemia. Occurs in about 25% of newborns weighing <2 kg, within the first 4 d.

    • Tests: Head ultrasound. Should be performed as a screen in all newborns <32 wk gestation and in symptomatic newborns >32 wk. Follow PIVH with serial US; 10% will develop hydrocephalus.

    • Prevention: Avoid premature birth. Avoid blood pressure fluctuations with therapeutic paralysis of vented newborns, rapid volume expansion.

    • Management: Continue BP control; treat hydrocephalus with drugs that decrease CSF production (e.g., mannitol, acetazolamide), EVD, or ventriculoperitoneal shunt.

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• Structural malformations:

  • Neurulation disorders: E.g., encephaloceles, myelomeningoceles: when spinal, AKA spina bifida. The defect should be surgically closed within the first week or two of life. Hydrocephalus requiring VP shunt usually develops because of associated aqueductal stenosis.

  • Midline malformations: E.g., holoprosencephaly (undivided anterior brain), septo-optic dysplasia.

  • Migration disorders: E.g., schizencephaly (brain cleft from partial defect in neuronal germinative zone), lissencephaly (agyria), pachygyria (few gyri), polymicrogyria.

  • Differentiation disorders: E.g., microcephaly, megalencephaly, neurocutaneous disorders, corpus callosum aplasia, Aicardi's syndrome (callosal agenesis with chorioretinal lacunae, vertebral defects, and infantile spasms in a girl), colpocephaly (enlarged occipital ventricular horns), congenital vascular malformations and tumors, porencephaly (cerebral cavity), hydranencephaly (severe bilateral porencephaly).

  • Cerebellar malformations:

    • Chiari malformation: See also p. 181 for radiologic appearance of tonsillar herniation. Sx range from headache to sx of cerebellar and brainstem compression.

      • Type I: Cerebellar tonsils herniate below the foramen magnum.

      • Type II: Cerebellar vermis, fourth ventricle, and medulla are below the foramen magnum. Usually with myelodysplasia and lumbar myelomeningocele.

      • Type III: Brain displaced into a myelomeningocele. Rare.

      • Dandy-Walker malformation: Vermis hypoplasia with fourth ventricle cyst and hydrocephalus, from blocked foramen of Magendie. Both the fourth and lateral ventricles must be shunted.

    • Myelination disorders.

    • Arachnoid cysts: Seen in 4% of normals; only 20% are symptomatic, usually from secondary hydrocephalus.

  • Chromosomal defects: E.g., trisomies, translocations, deletions, mosaicism.

    • Down syndrome (trisomy 21): 1/1,000 live births.

      • General features: Short, dysmorphic, simian crease; cardiac, thyroid, GI problems; increased risk of leukemia.

      • Neurological features: Hypotonia, mental retardation, early Alzheimer's dz, cervical narrowing and risk for atlantoaxial subluxation, seizures in 10%, nystagmus and sluggish pupils, hearing loss.

    • Fragile X syndrome: see p. 151.

  • Gene disorders: May be static or progressive (see p. 132).

  • Maternal diseases and toxins:

    • Fetal alcohol syndrome: Dx requires sx in each of three categories:

      • Growth retardation: Weight, length, or head circumference <10th percentile (corrected for gestational age).

      • CNS involvement: Neurological abnormality, developmental delay, or cognitive impairment.

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      • Facial abnormalities: 2 of the following: head circumference <3rd percentile; narrow eye slits; flat and long upper lip; underdeveloped midface; flat nose bridge.

    • Other: TORCH infections (p. 142), prenatal cocaine.

  • Postnatal insults: E.g., infections, malnutrition, toxins, cerebrovascular events, trauma, neglect.