congenital brain malformations

Question 1

formation of neural tube progression
neural plate? day \_\_
closure cranial end? day \_\_
closure caudal end? day \_\_
forebrain dev? day \_\_

Answer 1

18
24
26
28

Question 2

protrusion from brain through opening in skull?

Answer 2

encephalocele aka cranium bifidum

Question 3

malformation at anterior end of neural tube?
no brain and skull
frog like appearance

Answer 3

anencephaly

Question 4

most common neural tube defect?

involved caudal end of spinal cord

Answer 4

spina bifida

Question 5

spina bifida occulta?

Answer 5

vertebral bone defect bone alone

Question 6

protrusion through bone through meninges?

Answer 6

meningocele

Question 7

1. abnormal neuron #
2. improper migration
3. abnormal organization

Answer 7

3 causes of malformation of cortical dev

Question 8

megancephaly

Answer 8

inc neurons bc too few cells exited early

Question 9

microencephaly

Answer 9

decreased neurons bc too many cells exit early

Question 10

complete absensce of migration from ventricles

Answer 10

periventricular heteroptia

Question 11

partial migration to neocortex, large # stay behind = no normal cortical layer formed

Answer 11

lissencephaly

Question 12

1. no migration - perivent heteroptia
2. partial migration - lissencephaly
3. late migration disrupted - polymicrogyria
4. holoprosencephaly -forebrain doesnt divide in 2

Answer 12

4 mech for abnormal neuronal migration

Question 13

late stage migration and organizations disrupted, results in irreg formed gyri with cobblestone like appearance

Answer 13

polymicrogyria

Question 14

absense of forebrain division int 2 hemi - effects can rand from ABSENCE of OLFACTORY BULBs (arrhinecephaly) to complete absence of hemi/lobes and midline facial defect (ie cyclopia)

Answer 14

holoprosencephaly - brain is small and lacks lobes. eyes are small and malformed - maybe only ONE eye.

Question 15

fail to dev cerebellar vermis
massive dilated 4th ventricles
absent or small cerebellum
hydroceph

Answer 15

DANDY WALKER MALFORMATION

Question 16

downward tonsillar herniation through foramen magnum
hydrocephalus
s/s: headache
childhood
often with meningomyelocele and syringomyelia

Answer 16

arnold chiary malformation type II

Question 17

downward herniation of tonsils WITHOUT involved brainstem
can be as symptomatic
MOST COMMON FORM
teens/adults

Answer 17

chiari type I

Question 18

dilation of spinal canal by CSF

Answer 18

hydromyelia

Question 19

fluid filled cavity within cord leading to cystic degneration
seen in chiari type I - or 2ndary to injury
destroys white/grey matter
horner syn
involved in C8-T1 - sensory loss pain/temp
touch/position PRESERVED

Answer 19

syringomyelia