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Neuro_Week1 > Congenital Disorders I > Flashcards

Congenital Disorders I Flashcards

1
Q

when does neural tube closure take place?

in general all neural tube dz related to?

A

during week 3 –> so see defects

failure of NT to close properly or failure of NT to separate from overlying ectoderm (can cause tethered spinal cord)

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2
Q 
NT defect (0-4 wks)
mechanism of cranioraschisiss totalis
A
  • most severe defect
  • complete failure of NT to close –> leaving plate where actual NT should be

lethal

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3
Q 
NT defect (0-4 wks)
mechanism of anencephaly
A

failure of rostral neuropore to close

forebrain neuroectoderm doesn’t separate from cutaneous ectoderm –> red area cerebrovasculosa protruding out of head

“bug eye” b/c diencephalon does develop

lethal

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4
Q 
NT defect (0-4 wks)
mechanism of encephalocele
A

defect in skull with protrusion of leptomeninges and/or brain

different from anencephaly because epidermal covering over protrusion

possibly survive

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5
Q 
NT defect (0-4 wks)
mechanism of myelomeningocele
A

failure of posterior neuropore to close

80% in lumbar area –> kids have urinary and gait problems

no epidermal covering + CSF leak

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6
Q 
NT defect (0-4 wks)
mechanism of meningocele
A

skin covered CSF filled mass continuous with CSF in spinal cord

usu rest of tissue of cord is normal

kids have urinary and gait problems

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7
Q 
NT defect (0-4 wks)
lipomyelocele/lipomyelomeningocele
A

Lipoma extends from subcutaneous tissue to dorsal aspect of cord, tethering cord infeirorly

cause = premature separation of cutaneous ectoderm during neurulation allowing mesenchyme to enter unclosed NT and diff into fat

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8
Q 
NT defect (0-4 wks)
dorsal dermal sinus tract
A

ectoderm lined tract that crosses dura and allow CSF and skin to communicate

can tether spinal cord and/or assoc with intradural dermoid cyst or epidermoid

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9
Q 
NT defect (0-4 wks)
spina bifida occulta
A

occurs at L5-S1
occurs when bony lamina of vertebral body fails to close over portion of meningeal sac
usu no sx but can have cutaneous abnormality

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10
Q

NT defect (0-4 wks)

disease assoc with spinal cord tethering (all caudal derived)

A

myelomeningocele
lipomyelocele/lipomyelomeningocele
dorsal dermal sinus tract
spina bifida occulta

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11
Q

NT defects can be prevented with

A

preconception folic acid supplementation

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12
Q

holoprosencephaly

occurs when

A

cleavage of prosencephalon during week 5

occurs when single ventricle in early forebrain fails to form two lateral ventricles and 1 3rd ventricle (complete or partial)–> failure of 2 cerebral hemispheres to divide properly

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13
Q

3 types of holoprosencpephaly

A

1) alobar
2) semilobar
3) lobar

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14
Q

disorders of telencephalic development (~4-8 wks)

define alobar holoprosencephaly

A 
no evidence of division of cerebral cortex
1 forebrain, 1 ventricle 
fusion of thalami 
assoc with cleft lip/palate
severe facial abnormality
(most severe--> lethal)
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15
Q

disorders of telencephalic development (~4-8 wks)

define semilobar holoprosencephaly

A

partial cleavage of hemispheres with fusion of frontal lobes

horseshoe central ventricle

some fusion of thalami

no olfactory bulbs/corpus callosum

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16
Q

disorders of telencephalic development (~4-8 wks)

define lobar holoprsencephaly

A

hemispheres separated anteiorly and posteriorly with some fusion

  • least severe
  • normal life expectancy with severe mental/physical
17
Q

disorders of telencephalic development (~4-8 wks)
in general facts

1) genetic or not?
2) what gene involved
3) assoc with what chromosome

A

1) strong genetic
2) shh
3) assoc with trisomy 13

18
Q

disorders of telencephalic development (~4-8 wks)

Type of deformities common?

A

4) facial deform with

  • cebocephaly- hypotelorism, 1 nostril
  • cyclopia
  • ethmocephaly-
  • arhinia
  • coloboma of iris and retina
  • premaxillary agenesis (no nares or philtrum)
  • midline facial clefts (cleft lip)
19
Q

Disorders of cerebellar development (8-15 wks)

cerebellar aplasia

A

complete absence of cerebellum

20
Q

Disorders of cerebellar development (8-15 wks)

dandy walker

A

most common

includes

a) partial or complete absence of vermis
b) cystic dilation of 4th ventricle
c) upward displacement of tentorium

assoc with cerebral/visceral but NOT NTDs or MATERNAL FOLATE

21
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

MEGALENCEPHALY

A

too many neurons = too big brain

sx = delayed development
convulsions
corticospinal dysfunction
seizures

22
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

microcephaly
a) primary microcephaly

A

too few neurons
multifacotral

2 copies of loss of fxn mutation in microcephalin gene

decr life expectancy
poor prognosis

23
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/
problems with onset of migration

Periventricular heterotopia

inheritance
mutation

A

X linked dominant
lethal in males

mutation in FLNA so neurons can’t leave VZ

female PH = epilepsy but no cog abnormalities

24
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

problems in migration process
type 1 lissencephaly

gene
sx

A

neurons exit VZ but halt migration premature

brains smooth (agyria)

LIS 1 = gene (heterozygous, haploinsufficiency)
–> severe mental retard + epilepsy

25
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

problems in migration process
double cortex syndrome

A

neurons exit VZ but halt migration premature

DCX (x chromosome)
males = can’t diff from lissencpehaly (more serious)

females = 1 mutant DCX = double cortex (epilepsy + mild retard + subcortical band heterotopia)

26
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

problme in stopping migration

lissencephaly with cerebellar hypoplasia

A

mutation in reeler gene

neurons can’t get off radial glia

inverted inside out

assoc with cerebellar problems (reeling gait)

27
Q

Disorders/of/Proliferation// Migration/(8.20/wks)/

polymicrogyria

A

abnormal distrib of neurons in 6 layers of cortex –> small gyri

most common affects posterior sylvian fissure

assoc with severe motor and intellect dysfunction

assoc with CMV

28
Q

NTD can manifest as ___

A

cutaneous defects (dermal dimple, patch of hair, lipoma, hemangioma)

29
Q

lab value in NTD

A

high maternal or amniotic AChE @ 12-14 wks

30
Q

freq common findings in tethered cord with NTD

A

tethered ccord = spasticity in muscles, hyperreflexia, urinary incontinence

31
Q

describe chiari 1 malformation

assoc with what

symptoms

A

elongated cerebellar tonsils pushed thru foramen magnum blocking flow of CSF

mesodermal disorder of occipital somites and bony posterior fossa

bilateral loss of pain and temp in cape like distribution
UMN symptoms below level of syrinx

hydromelia, syringomyelia, myelopathy

32
Q

describe hydromelia

A

obstruct CSF exit from central canal of cord into subarach space –> accum of CSF in central canal

33
Q

describe syringomyelia

A

CSF cyst that breaks out of canal and dissects cord (not NTD)

34
Q

describe myelopathy

A

dysfunction of gray or white matter of cord

35
Q

describe chiari 2 malformation

A

elongation of cerebellar vermis and push thru formaen magnum

causes beaking of midbrain tectal plate, “z kink medulla”

causes low lying confluence of sinuses
osseous abnormalities in skull

assoc with thoraco-lumbar myelomeningocele

36
Q

major symptoms assoc with chiari malformations

A

headache with coughing

Neuro_Week1 (26 decks)

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