Chapter 60 Fetal Neural Axis Flashcards

1
Q

CNS arises from the ectodermal neural plate around _____

A

18 days gestation

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2
Q

Cephalic neural plate develops into the

A

forebrain

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3
Q

the caudal end forms the

A

spinal cord

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4
Q

the forebrain develops into the

A

Prosencephalon

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5
Q

the mesencephalon develops into the

A

midbrain

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6
Q

the rhombencephalon develops into the

A

hindbrain

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7
Q

by the end of the 3rd week, the cephalic end of the neural tube bends into a ____ shape

A

c-shape

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8
Q

in the ____ week, the neural tube bends again

A

5th

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9
Q

The prosenceohalon divides into the

A

Telencephalon and diencephalon

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10
Q

Telencephalon becomes the

A

Cerebral hemispheres

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11
Q

Diencephalon becomes the

A

Thalamus

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12
Q

Rhombencephalon divides into the

A

Metencephalon and mylencephalon

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13
Q

Metencephalon becomes

A

Cerebellum and pons

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14
Q

Mylencephalon becomes

A

Medulla

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15
Q

Neural function begins at

A

6 weeks gestation

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16
Q

Between _____ the fetus can grip objects and is capable of weak respiratory movements

A

4-5 months

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17
Q

Fetus displays sucking reflux at ____

A

6 months

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18
Q

Most common neural tube defect

A

Anencephaly

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19
Q

Absence of brain and skull

A

Anencephaly aka aprosencephaly/atencephaly

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20
Q

Risk of anencephaly can be reduced by 50-70% with use of ______ supplements beginning 1 month before pregnancy

A

Folic acid

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21
Q

Caused by failure of the neural tube at the cranial end. Resulting in absent cranial vault, complete/partial absence of forebrain

A

Anencephaly

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22
Q

Prenatal diagnosis of anencephaly is often made with sonography, following a lab value of ___

A

Elevated AFP

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23
Q

Causes for anencephaly:

A

Diabetes, Meckel-Gruber syndrome

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24
Q

Sonographic findings of anencephaly:

A

Bulging fetal orbits—frog face appearance

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25
Q

Absence of skull

A

Acrania

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26
Q

Acrania is also known as

A

Exencephaly

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27
Q

Absence of cranial bones with the cerebral hemispheres still there(although abnormal)

A

Acrania

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28
Q

Acrania usually progresses to anencephaly because:

A

Brain slowly degenerates from exposure to amniotic fluid

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29
Q

How to distinguish acrania from anencephaly:

A

Presence of significant brain tissue and lack of frog-face appearance indicated acrania

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30
Q

Neural tube defect in which meninges alone or meninges and brain herniate through a defect in the skull

A

Cephalocele

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31
Q

Herniation of meninges AND brain through defect

A

Encephalocele

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32
Q

Herniation of only meninges through defect

A

Cranial meningocele

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33
Q

Cephalocele more commonly involves the _____ bone

A

Occipital

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34
Q

Sonographic features of cephalocele:

A

Extracranial mass

Ventriculomegaly

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35
Q

Autosomal recessive disorder characterized by encephalocele, polydactyl, polycystic kidney disease

A

Meckel-Gruber syndrome

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36
Q

Cephalocele may be confused with

A

Cystic hygroma

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37
Q

Chromosomal anomalies and syndromes associated with cephaloceles

A

Trisomy 13

Meckel-Gruber syndrome

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38
Q

Wide range of defects that result from failure of neural tube to close

A

Spina bifida

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39
Q

Spina bifida most commonly occurs along the ____ and ____ region

A

Lumbar and sacral

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40
Q

The term spina bifida means

A

There is an cleft/opening in the spine

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41
Q

Spina bifida occulta is extremely difficult to detect if

A

Defect is covered by skin

AFP is normal

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42
Q

Spinal opening covered in skin, commonly with a tuft of hair

A

Spina Bifida Occulta

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43
Q

Sounds bifida term used when defect only involves the protrusion of meninges

A

Meningocele

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44
Q

Sounds bifida term used when both meninges & neural elements protrude through defect(more common)

A

Meningomyelocele

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45
Q

Sounds bifida term used when defect is very large and severe

A

Rashcischisis

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46
Q

Raschischisis is associated with increased

A

AFP

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47
Q

Most fetus(90%) with myelomeningocele present with cranial defects associated with

A

Arnold-Chiari 2 malformation

48
Q

Arnold-Chianti 2 malformation is ____ shaped appearance of the cerebellum

A

Banana

49
Q

Arnold-Chiari 2 malformation leads to obliteration of the

A

Cisterna magna

50
Q

Due to increased intracranial pressure during spina bifida, the skull will be ____ shaped

A

Lemon shaped

51
Q

The best plane to evaluate the spine for spina bifida is:

A

Transverse

52
Q

Normal spine should be triangular or circular, with spina bifida (meningomyelocele) the splaying of the posterior ossification centers makes a

A

V or U shape

53
Q

Intracranial findings with spina bifida

A

Ventriculomegaly
Banana shaped cerebellum
Lemon shaped skull
Cisterna magna obliteration

54
Q

Spina bifida is associated with chromosomal anomalies and syndromes like:

A

Trisomy 18

55
Q

Maternal risk factors for spina bifida:

A

Diabetes, obesity, folic acid deficiency, hyperthermia

56
Q

Rare, occiput is fused to the cervical region

A

Iniencephaly

57
Q

Defect in occiput involving the foramen magnum, retroflexion of spine causes fetus to look upward: ____ sign. This is ____

A

Stargazing sign

Iniencephaly

58
Q

cerebellar lobes “go for a walk”

A

Dandy-Walker Malformation

59
Q

Agenesis or hypoplasia of the cerebelar vermis, resulting in 4th ventrical dilation and enlargement of posterior fossa

A

Dandy-Walker Malformation

60
Q

50% of the time, Dandy-Walker Malformation is associated with

A

Agenisis of the corpus collosum

61
Q

Dandy Walker Malformation encompasses 3 types of posterior fossa malformations:

A

Elevated tentorium(tent of the cerebellum)

Dialation of 4th ventricle & hypoplasia of cerebellar vermis w/o enlargement of posterior fossa

Megacisterna magna(large Cisterna magna)

62
Q

Diagnosis of agenesis or hypoplasia of vermis shouldnt be made until ____ week

A

18 weeks gestation

63
Q

Vermis begins to develop during

A

9th week

64
Q

4th ventricle and cisterna magna are complete:

A

18 weeks

65
Q

Extracranial abnormalities associated with Dandy-Walker Malformation(DWM):

A

Cardiac anomalies

66
Q

Sonographic features of DWM:

A

Large posterior fossa cyst

Enlarged cisterna magna, ventriculomegaly

67
Q

How would you differentiate a posterior fossa cyst from a subarachnoid cyst

A

PFC communicates with the 4th ventricle

68
Q

Holoprosencephaly results from abnormal cleavage of

A

Prosencephalon

69
Q

3 forms of holoprosencephaly

A
  1. Lobar(mild)
  2. Semi-lobar(middle)
  3. Alobar(worst)
70
Q

Holoprosencephaly: Singular, monoventricle brain tissue that js small(may have cup, ball, pancake configuration). Absence of pretty much everything

A

Alobar

71
Q

Alobar holoprosencephaly involves fusion of the ____

A

Thalamus

72
Q

Holoprosencephaly: Singular ventricular cavity with partial formation of occipital horns, falx & interhemispheric fissure

A

Semi-lobar

73
Q

Holoprosencephaly in which the corpus collosum may still be present

A

Lobar

74
Q

Sonographic features of holoprosencephaly

A

C-shaped ventricle

Horseshoe shaped brain tissue surrounding that ventricle

Absent CSP

75
Q

Facial clefts may be oresent with holoprosencephaly, most commonly they are

A

Medial or bilateral

76
Q

Hypotelorism with normally placed nose with single nostril

A

Cebocephaly

77
Q

Severe hypotelorism with probiscis superior to eyes

A

Ethmocephaly

78
Q

Fibrous tract that connects the cerebral hemispheres that aids in learning and memory

A

Corpus collosum

79
Q

Agenesis of the corpus callosum is thought to involve _____ or inflammatory lesions before 12 weeks

A

Vascular disruption

80
Q

Maternal diseases contributing to a genesis of the corpus callosum

A

Diabetes

81
Q

Sonographic features of agenesis of the corpus callosum

A

Teardrop shaped lateral ventricle

absent cavum septum pellucidum

82
Q

Aqueductal stenosis results from obstruction or stenosis of the

A

Aqueduct of Sylvius

83
Q

Sonographic features of aqueductal stenosis

A

Dilation of third ventricle, lateral ventricle enlargement

84
Q

Rare arteriovenous malformation, predominantly occurs in males, associated with congenital heart defects

A

Vein of Galen Aneurysm

85
Q

Vein of Galen aneurysm prognosis is especially poor when associated with

A

Hydrops or cardiac failure

86
Q

Primary treatment for Vein of Galen aneurysm

A

Embolism

87
Q

Vein of Galen aneurysm will show ____ flow with Doppler

A

Turbulent

88
Q

Cystic space that may be a regularly shaped and located midline and posterosuperior to the third ventricle indicates:

A

Vein of Galen aneurysm

89
Q

Choroid plexus cysts may be associated with

A

Trisomy 18

90
Q

Cysts filled with CSF that communicate with the ventricular system or subarachnoid space. No known associated anomalies.

A

Porencephalic cysts/porencephaly

91
Q

Post natal problems from porencephalic cysts/porencephaly may include

A

Seizures

92
Q

Rare disorder characterized by clefts in the cerebral cortex

A

Schizencephaly

93
Q

Schizencephaly is usually in the area of the _____

A

Sylvian fissure

94
Q

Schizencephaly is linked with ___

A

Multiple assaults during pregnancy

95
Q

In schizencephaly, _____ and ____ carry a wkrse prognosis

A

Open lip lesion and bilateral clefts

96
Q

Sonographic features of schizencephaly

A

Ventriculomegaly

Fluid-filled cleft in cerebral cortex extending from ventricle to calvarium

97
Q

Absent or reduced cerebral convolutions, brain lacks sulci and gyri, therefore is appears smooth

A

Lissencephaly

98
Q

Diagnosis of lissencephaly cannot be made until

A

3rd trimester

99
Q

Destruction of cerebral hemispheres by occlusion of the internal carotid arteries

A

Hydranencephaly

100
Q

Coexisting chromosomal and stuctural anomalies associated with hydranencephaly

A

None

101
Q

Hydranencephaly is associated with

A

Polyhydramnios

102
Q

With hydranencephaly, brain ischemia may result from

A

Maternal hypotension

103
Q

Sonographic features of hydranencephaly

A

Absense if normal brain tissue with almost complete replacement by CSF

Absent or partially absent falx

104
Q

How do you differentiate hydranencephaly from hydrocephaly?

A

Look for the midline falx— if its gone it will be hydranencephaly

Hydranencephaly wont demonstrate the dangling choroid sign, hydrocephaly will

105
Q

Dilation of the ventricles within the brain secondary to an increase in CSF volume

A

Ventriculomegaly/hydrocephalus

106
Q

Ventriculomegaly/hydrocephalus can be either ____ or ______

A

Communicating or noncommunicating

107
Q

Ventriculomegaly/hydrocephalus:

Obstruction cause by ventricular defect(aqueduct Sylvius):

A

Noncommunicating hydrocephalus

108
Q

Ventriculomegaly/hydrocephalus:

Obstruction outside the ventricular system:

A

Communicating hydrocephalus

109
Q

Associated abnormalities with ventriculomegaly/hydrocephalus:

A

Aqueductal stenosis

Vein of Galen aneurysm

110
Q

Common causes of ventriculomegaly/hydrocephalus:

A

Spina bifida

Encephaloceles

111
Q

Sonographic features of hydrocephalus/ventriculomegaly

A

Dangling choroid sign

112
Q

What differentiates hydrocephalus/ventriculomegaly from hydranencephaly and holoprosencephaly?

A

Presence of complete falx, choroid plexus, 3rd & 4th ventricles

113
Q

Abnormally small head that falls 2 standard deviations below the mean

A

Microcephaly

114
Q

Factors linked with microcephaly

A

Alcohol abuse, heroin addiction, mercury poisoning

115
Q

Microcephaly is usually associated with ______

A

Neurological deficits

116
Q

Sonographic features of microcephaly

A

Abnormal measurements

Cerebral calcifications with congenital infections

Clover-leaf skull