CNS Development

Question 1

4 types of dysraphic defects or dysraphism:

Answer 1

anencephaly
encephalocele
chiari malformation
spina bifida

Question 2

anencephaly is:

Answer 2

brain stem and thalamus, usually diagnosed in prenatal ultrasound

Question 3

encephalocele:

Answer 3

cyst herniating through skull defect, causes developmental delay and seizures

Question 4

less severe form of encephalocele is:

Answer 4

meningeocele: only meninges and csf bulging out, primarily just cosmetic

Question 5

most severe form of encephalocele:

Answer 5

when part of the brain and 4th ventricle are bulging out: dura csf brain ventricle, usually occipital

Question 6

spina bifida:

Answer 6

myeloschisis: spine is separated, closed “occulta” (skin covers the defect), or open “aperta”, meningocele (meninges bulging out) or meningomyelocele (meninges and spinal cord bulging out)

Question 7

malformation associated with spina bifida aperta:

Answer 7

arnold chiari malformation type II, herniation of medulla, cerebellar vermis below level of foramen magnum, may cause hydrocephalus (can close off cerebellar aquaduct and cause hydrocephalus)

Question 8

2 main forms of hydrocephalus:

Answer 8

communicating (no reabsorption of cfs) there is communication across the aquaduct/obstructive: (obstruction of outflow)

Question 9

What are the signs and symptoms of spina bifida?

Answer 9

Below level of meningocele/meningomyocele:
Weakness
Sensory loss
Loss of bowel/bladder and sexual function
From hydrocephalus:
Progressive enlargement of head size
Vomiting
Death if not shunted

Question 10

spina bifida with bulging lower spine and no neurological defects:

Answer 10

meningeocele

Question 11

defects of the Prosencephalon include:

Answer 11

abnormal separation of the lobes of the brain: holoprosencephaly (alobar, semilobar, lobar) septo-optic dysplasia, midline defect

Question 12

holoprosencephaly/septo-optic dysplasia can be caused by:

Answer 12

4-5 week (trisomomy 13 or 18) alcohol, maternal diabetes, torch infections (Toxo, Rubella, CMV, HSV, HIV)

Question 13

3 levels of _______ (degree of severity) includes

Answer 13

holoprosencephaly; (normal)-lobar-semilobar-alobar

Question 14

Baby boy born at 37 wks gestation
Large ventricles noted on prenatal US
At birth, noted to have a large head with cranial sutures widely separated
2 cm cystic lesion in lumbar area
Child underwent closure of spinal defect on day 2 of life
Ventriculo-peritoneal shunt placed to drain hydrocephalus on day 13 of life to drain CSF
At age 8, he is a happy, healthy little 3rd grader
Given the lack of neurologic deficit, this pt was most likely born with

Answer 14

Myelomeningocele
Encephalocele
Meningocele
Meningoencephalohydrocele
Spina bifida oculta

Question 15

semilobar is a _____ disorder in which there is _____ of ______ and _________

Answer 15

holoprosencephaly disorder, incomplete separation of the frontal lobe and separation of the occipital lobe

Question 16

semilobar holoprosencephaly results in:

Answer 16

single nostril, shallow nasal bridge, close set eyes

Question 17

if you have a cyclopse baby it is:

Answer 17

halolobar

Question 18

Holoprocencephaly are caused by:

Answer 18

4-5 week (trisomomy 13 or 18) alcohol, maternal diabetes, torch infections (Toxo, Rubella, CMV, HSV, HIV)

Question 19

microencephaly:

Answer 19

primary, genetic, injury, infection after normal cortical development (inside out)

Question 20

hemi-megaencephaly:

Answer 20

the neuronal cells go to the right place but there are just too many of them!

Question 21

3 types of neuronal migration disorders:

Answer 21

gray heterotopia, Lissencephaly, schizencephaly

Question 22

neurons are supposed to migrate from the exterior to the center of the brain and never make it. Ends up with:

Answer 22

lissencephaly, scizencephaly (didn’t close one side so it remains open to the ventricle)