Atypical CNS Development - Quiz 8

Stages of embryo development where CNS is at risk

o Cell divisions

o Failure of neural tube to close

o Failure of neuropores to close

o Cell migration

o Pruning

o Cell differentiation

o Chemical signaling of CNS developmental event

environmental exposure, in utero stroke, premature birth, genetics

Factors that can negatively affect embryological/fetal CNS development include:

environmental exposure

§ Maternal inputs

· Infection

· Blood pressure

· Trauma

§ Exposure to

· Pharmaceuticals

· Alcohol

· Heavy metals

· Toxins

§ Disruption of fetal blood supply

§ Maternal nutritional deficiencies

Are examples of which factor type that can negatively affect fetal CNS development?

Arnold Chiari Malformation Type I

Herniation of the cerebellar tonsils through the foramen magnum. Both medulla and pons are small and deformed. (developmental deformity of the hindbrain)

Arnold Chiari Malformation Type I

Usually asymptomatic but symptoms may occur during adolescence or early adulthood. Symptoms include:

§ Severe head and neck pain

§ May be associated with restricted CSF flow resulting in hydrocephalus

§ Malformation of cerebellum and lower cranial nerves may result in tongue and facial weakness, decreased hearing, dizziness, weakness of lateral eye movements, problems with coordination

§ Visual disturbances may occur because of CSF in the third ventricle pressing on the optic chiasm

Arnold Chiari Malformation Type II

Malformation of the brainstem and cerebellum, leading to extension of the medulla and cerebellum through the foramen magnum

Arnold Chiari Malformation Type II

Symptoms in infancy

Often causes progressive hydrocephalus, paralysis of SCM, deafness, bilateral weakness of lateral eye movements, and facial weakness

Almost always associated with myelomeningocele

Spina Bifida

Failure of the inferior neuropore to close. Developing vertebrae do not close around an incomplete neural tube, resulting in a bony defect at the distal end of the tube

Spina Bifida

Associated with maternal nutrition (deficit of folic acid), maternal seizure medication (valproic acid), genetics (Celts, Hispanic)

spina bifida occulta

vertebral arch is open, but no protrusion of nervous tissue, "hidden," usually asymptomatic

spina bifida cystica

meninges and in some cases spinal cord protruding through the absent vertebral arch and having the appearance of a cyst

spina bifida meningocele

herniation of the meninges through the bony defect

spina bifida myelomeningocele

hernia of the neural tissue and meninges

spina bifida myelomeningocele

results in abnormal growth of the spinal cord, some degree of LE dysfunction, B&B, associated cognitive defects (cocktail personality)-difficulty with abstract reasoning, visual perception, and visual motor integration

Spina bifida myeloschisis

malformed spinal cord open to the surface of the body, occurs when spinal folds fail to close

Anencephaly, Meroencephaly

Cranial end of the neural tube (rostral neuropore does not close in 4th week) remains open and the forebrain does not form resulting in a rudimentary brainstem without cerebral and cerebellar hemispheres

Anencephaly, Meroencephaly

Causes: chromosomal abnormalities, maternal nutritional deficiencies, maternal hyperthermia

Microcephaly

Brain is small but the face is normal size

Significant developmental delays

Results from a reduction in brain growth

Cranium is small because its size is driven by brain growth

Microcephaly

Causes:

genetic

maternal infections: Zika virus, rubella, toxoplasmosis, cytomegalovirus

severe malnutrition

exposure to alcohol

certain drugs or toxic chemicals

ionizing radiation

interruption to the blood supply to the baby's brain during development

Holoprosencephaly

Failure of the embryonic forebrain to divide into 2 lobes that will eventually become the cerebrum

Holoprosencephaly

o 3 classifications: Alobar, Semilobar, Lobar

o Characterized by craniofacial defects

§ Mild: microcephaly, midface flattening, closely spaced eyes, flat nasal bridge, cleft lip

§ Severe: single eye, missing nose or proboscis (tubular nose)

Schizencephaly

Characterized by abnormal clefts or slits in the cerebral hemispheres

Commonly have aplasia/hypoplasia of the corpus callosum, EEG abnormality/seizures, strabismus, global developmental delays, hypotonia, hydrocephalus

Schizencephaly

Causes/risk factors: genetic, young maternal age, certain medications and infections that cause vascular disruptions in the developing baby

Lissencephaly

"Smooth Brain" rare, genetic brain malformation characterized by the absence of gyri and microcephaly.

Caused by defective neuronal migration during embryonic development

Lissencephaly

Symptoms include unusual facial appearance, difficulty swallowing, failure to thrive, muscle spasms, seizures, and severe global delays

agenesis of the corpus collosum

Complete or partial absence of the corpus callosum

Caused by a disruption of cell migration during fetal development

agenesis of the corpus collosum

May be isolated but can be in combination with other cerebral abnormalities including Arnold-Chiari Malformation, Dandy-Walker Syndrome, schizencephaly, and holoprosencephaly.

May be asymptomatic but seizures, developmental delays, and intellectual disability are common

cerebral palsy

A group of permanent disorders of the development of movement and posture, causing activity limitations that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain

cerebral palsy

Umbrella term

Variation in presentation: monoplegia, hemiplegia, diplegia, quadriplegia

Spastic, ataxic, dystonic, hypotonic, mixed

Gross Motor Function Classification System: Levels I through V

May be accompanied by cognitive, sensory, behavioral, and communication disorders as well as seizures

Jon is a cool guy

This card is a reminder to review the 5 million causes of cerebral palsy.

Enter "Jon is a cool guy" to proceed.

autism spectrum disorder

Deficits in social communication and social interaction across multiple contexts

§ Social-emotional reciprocity

§ Nonverbal communication

§ Developing, maintaining, and understanding relationships

developmental coordination disorder

Learning and performance of coordinated motor skills are not what would be expected based on a child's age

The motor difficulties have a significant impact on self-care, academic, leisure, and play activities

Difficulties begin early in development

attention deficit hyperactivity disorder

Show a persistent pattern of inattention and/or hyperactivity/impulsivity that interferes with functioning

gestational age

The time elapsed from the first day of the mother's last menstrual period (LMP) until birth or the current date. It is expressed in completed weeks and days

chronologic age

The time elapsed strictly after birth, measured in days, weeks, months, or years

conception age

The actual age of the fetus, measured from the exact moment fertilization occurs when a sperm merges with an egg