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66 Cards in this Set
- Front
- Back
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What percent of babies with holoprosencphally have chromosomal abnormalities
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more than 50 percent
chromosome 13 most commonly |
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What abnormality is associated with chromosome 13 trisomies
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holoprosencephaly
mid facial abnormalities |
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What is the ddx for moderately dilated ventricles (10-20mm)
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Chiari 2 (also has small posterior fossa low lying cerbellar tonsil large foramen magnum,elongated fourth ventricle, myelomeningocele)
dandy walker agenesis of corpus callosum (can be larger ventricles too) chromosomal abnormalities infection Isolated ventriculomegally |
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What is the size of moderate and severly enlarged ventricles
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moderately enlarged (10-20)
severly enlarged greater than 20mm |
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What do you want to look at if you see enlarged ventricles
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the posterior fossa (chiari 2 or dandy walker)
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What do you want to see on US when you examine a normal posterior fossa
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biconcave margin of the cerebellar hemisphere
with fluid surrounding it |
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What is evidence of a chiari malformatin in the posterior fossa on US
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small posterior fossa
banana sign? (posterior fossa) lemon sign? (anterior to frontal lobe) effeced cisterna magna low lying cerbellar tonsil large foramen magnum elongated fourth ventricle |
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What is a charachteristic of chiari II malformations
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open myelomeningoceles, ventriculomegally, small posterior fossa
not on US a low lying cerebellar tonsil, elongated 4th, ventricle, large foramen magnum |
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What part of the brain is a chiari malformation from
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a malformation of the hindbrain
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What does a myelomengiocele look like
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a sac in the lumbosacral spine
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What is lab test can be used to detect if a fetus has a myelomeningocele
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AFP (80-85%)
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What is a major cause of myelomengocele
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folate deficiency
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What is the ddx for fetal CNS anomalies
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holoprosencephaly
Chiari 2 and other neural tube defects choriod plexus cyst dandy walker malformation agenesis of the corpus callosum hyranencephally cephalocele aqueductal stenosis |
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Should the fetal ventricles be evaluated on every fetal US
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yes
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What is an indication that a fetus has ventriculomegally on US
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if during evaluatoin in the axial plane the choriod plexus is dangling down
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What is non-abnormal size of a ventricle
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less than 11mm (applies for entire gestation)
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What is the DDX for fetal ventriculomegally
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holoprosencephaly
dandy walker chiari 2 ACC aqueductal stenosis cephalocele infection hemorrhage trisomies |
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What is the ddx for very large ventricles (>20mm)
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hydranencephaly
holoprosencephaly aqueductal stenosis agenesis of the corpus callosum |
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What do you expect to see in hydranencephaly?
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calvarium without brain (cortical destruction occurs)
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What is the cause of holoprosencephaly
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failed cleavage of prosencephalon (4-6)
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Is there a falx in holoprosencephaly?
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no
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When do you see fused thalami?
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holoprosencephaly
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What are 3 characteristics of holoprosencephaly
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large ventricles
monoventricle fused thalami |
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What are 3 forms of holoprosencephaly
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lobar, semi-lobar, alobar
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On US what do you expect see in holoencephaly
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large ventricles
fused anterior cortex (no falx cerebri) dorsal cyst fused thalami hippocampal ridge |
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What are 4 types of facial anomalies associated with holoprosencephaly
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MID-facial hyperplasia:
cyclopia ethmocephaly cebocephaly midline cleft |
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Where is the most common location for myelomenigoceles
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lumbosacral
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What are 3 characteristics of a chiari 2 malformation
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small posterior fossa, hydrocephalus, myelomenigocele
(associated with neural tube defect) |
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What type of chiari defect is associated with posterior fossa malformation
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chiari 2
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What is anencephaly
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a lethal condition with symmetric abscence of the cranium
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What is the frequency of anencephaly
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1:1000
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Is AFP elevated in anencephaly
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yes (lots of neural tissue exposed to amniotic fluid)
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What is the angiomatous stoma
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this is bouyant free floating tissue in fetus's with anencephally that sometimes confuses the dx
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What is the ddx for anecephally
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amniotic band syndrome
microcephaly encephaloclele |
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If a fetus has anfiomatous stroma what may anencephaly be confused with
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encephalocele
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What is the 3rd MC neural tube defect
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cephalocele
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Is a cephalocele midline
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yes
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Where is the mc location for a cephalocele
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midline (occipital (75%)
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Is AFP elevated with cephaloceles
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not always (may be skin covered)
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What is the association with cephaloceles (meckel gruber syndrome)2
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renal dysplasia and polydactyly (autosomal recessive)
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What is the difference between a cystic hygroma and a cephalocele
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cephalocele- acute angle with scalp, skull defect, brain usually abnormal
cystic hygroma- obtuse angle with scalp, nuchal ligament, brain is usualy normal |
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On US if a fetus has a cystic hygroma in the occipital region what should u expect to see
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echogenic band centrally (nuchal ligament)
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What are the parts of the posterior fossa that should be identified on every fetus
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echogenic vermis
quadrigeminal plate cisterna magna |
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What disease has an absent or small vermis and a dilated 4th ventricle
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dandy walker malformation
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Does dandy walker have large dilated ventricles
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no they are usually mildly dilated or normal
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Do you need a vermis
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no, dandy walker is often diagnosed later in life (associated malformations in DW syndrome influence prognosis
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What is associated with dandy walker syndrome
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agenesis of the corpus callosum and cystic changes of the brain
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What percent of fetus with ageneisis of the corpus callosum have other abnormalities
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85
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What is associated with agenesis of the corpus callosum
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chromosomal abnormalities
chiari dandy walker lots of others |
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How do you diagnose the corpus callosum
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by indirect sign
(ventriculomegally, abnormal shape of the ventricles, absence of cavum septum pellucidum, high riding 3rd ventricle) |
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What is the shape of the ventricle
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tear drop ventricle (undilated anterior horn and more dilated occipital horns)
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What is the name of the shape of the ventricles in ACC
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colpocephally (undilated anterior horn with more dilated occipital horn to form a tear drop appearance)
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Why does ACC not have a septum pelucidum
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because corpus collusum and septum form together
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What is the postion of the 3rd ventricle in ACC
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high riding
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What is the ddx for abscence of the cavum septum pelucidum
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ACC
septo-optic dysplasia holoprosencephaly |
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What are 2 features septo-optic dysplasia
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optic nerve dysplasia
panhypopituitarism |
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What chromosomal abnormality is associated with choroid plexus cyst
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ch 18 (50% of these fetus)
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What are choroid plexus more commonly seen in a fetus with chromosome 18 abnormality or a normal fetus
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a normal fetus (occurs in 1-5% of these but there are many more)
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When is a fetus considered low risk with a choriod plexus cyst
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nl serum and antomic survey (no chromosomal screening necessary)
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What percent of fetus with chromosome 18 are dysmorphic
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75% (will pick this up on anatomic survey)
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What do the hands look like on chromosome 18
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clenched (65%)
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Do you follow a choroid plexus cyst
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no they all disappear
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Do choroid plexus cyst affect brain development
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no
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What has posterior fossa findings and a sac in the lumbosacral spine
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chiari 2 malformation
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Drapped ventricle over fused ventricles is
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holoprosencephaly (
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What is holoprosencephally associated with
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chromosome 13
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