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DMST 315 OBGYN 3 > Fetal Neural Tube Pathology > Flashcards

Fetal Neural Tube Pathology Flashcards

1
Q

What does the ventricles contain?

A

4 connecting cavities within the cerebral hemispheres of the brain stem

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2
Q

The ventricles are continuous with what?

A

The spinal cord cavity

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3
Q

The Cavum septi pellucidi are located where in relation top the thalamus?

A

Anterior and slightly superior

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4
Q

What does the cavum septi pellucidi separate?

A

The anterior horns of the lateral ventricles

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5
Q

What is the CSF flow pattern?

A
  1. Lateral ventricles
  2. Interventricular foramen (Munro)
  3. 3rd ventricle
  4. Cerebral aqueduct
  5. 4th ventricle
  6. Two foramen, Magendie and Luschka
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6
Q

What does the cavum septi pellucidi visualization signify?

A

Normal development of the frontal midline

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7
Q

The cavum septi pellucidi is a important landmark for what measurements?

A

BPD where the cranium is measured

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8
Q

What is the criteria for ventricular measurement? 3

A
  1. Measure ventricle farthest from the transducer
  2. Measure at the level of the parietal occipital fissure
  3. Perpendicular to the cavity, inner to inner or “on to on”
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9
Q

Label the difference between the two

A

The left box is the CSP and the right box is the Fornix

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10
Q

What does the normal 3rd ventricle look like? And where is it located?

A
  1. Thin
  2. Located between the thalami and inferior to the corpus callosum
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11
Q

Where is the 4th ventricle located?

A

Anterior and inferior edge of the cerebellum

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12
Q

What is hydrocephalus?

A

Increase in CSF that results in enlargement of the ventricular system

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13
Q

Hydrocephalus is usually due to what? 2

A

Obstruction along the pathway of the CSF

  1. Intraventricular
  2. Extra ventricular
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14
Q

What is the most common cranial anomaly?

A

Hydrocephalus

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15
Q

What are causes of hydrocephalus? 2

A
  1. True hydrocephalus
  2. Ventricularmegaly
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16
Q

What is true hydrocephalus?

A

CSF obstruction

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17
Q

How would we get ventricularmegaly? 2

A
  1. Brain atrophy
  2. Small brain, ventricle have space to enlarge into
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18
Q

What are causes of true hydrocephalus? 3

A
  1. Neural tube defect
  2. Aqueduct stenosis
  3. Dandy walker malformation
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19
Q

What causes aqueduct stenosis? What does the lateral and 3rd ventricles look like? What about the 4th?

A
  1. CSF can not flow from 3rd ventricle to 4th
  2. Lateral and 3rd ventricle are enlarged
  3. 4th ventricle is normal
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20
Q

What causes intraventricular obstruction?

A

Aqueduct stenosis

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21
Q

What are some extra ventricular obstruction? 4

A
  1. Spina bifada
  2. Excess CSF
  3. Dandy walker malformation
  4. Sacral tumors
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22
Q

What is spinda bifida?

A

CSF can not flow normally through spinal canal and backs up in the ventricle of the brain

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23
Q

Which ventricles are affected by spina bifida?

A

All ventricles are affected

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24
Q

Excess secretion of CSF causing extraventricular obstruction comes from where?

A

Excessive section from a choroid plexus

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25
How do we evaluate ventricular size?
Measure ventricular atrial diameter
26
Ventricular diameter does not change much from which dates?
15-35 weeks
27
What is the typical ventricle measurement ?
Around 7mm
28
What is the upper limit of normal for ventricular size?
10mm
29
What is the distance from medial ventricle wall to choroid?
<3mm
30
Additional anomalies occur in what percentage of cases of hydrocephalus?
70-80%
31
What are some things we see with posterior fossa views? 2
1. Cisterna magna and cerebellum 2. Skull deformities
32
What do we assess for in the cistern a magna and cerebellum? (What signs do we look for) 2
1. Assess for obliterated cisterna magna, Cerebullum right up against the posterior skull 2. Banana sign
33
What is dandy walker malformation? 2
A condition having 1. Enlarged cisterna magna 2. A defect in the cerebeller vermis
34
With DWM the cisterna magna communicates with the 4th ventricule how?
4th ventricle through the defect in the cerebellum
35
With DWM the ventricles may appear how?
Enlarge due to pressure in the posterior fossa
36
The DWM variant occurs when there is what?
Occurs when there is partial agenesis of the cerebella’s vermin’s, with smaller cisterna magna, and minimal dilation of the ventricles
37
Both DWM and DWM variant is associated with what?
Many syndromes
38
DWM is associated with what conditions? 6
1. Agenesis of the corpus callosum 2. Heart defects 3. Genitourinary anomalies 4. Polydactyly 5. Intellectual impairment is common 6. Fetal death is common
39
What risk factors increase the incidence of DWM? 3
1. Maternal viral infection 2. Alcohol consumption 3. Diabetes
40
In terms of DWM, how big does the cisterna magna have to be to be abnormal?
> 1cm is abnormal
41
The cerebeller view of DWM must include what? 3
1. Cavum septi pellucidi 2. Peduncles 3. Cerebellum
42
When assessing DWM what do we try to prove? 3
1. Is the cisterna magna communicating with the 4th ventricle 2. Is the cerebeller vermis absent or partially absent 3. Are the ventricles enlarged?
43
What is the DDX for DWM? 2
1. Arachnoid cyst in posterior fossa *fluid collections in the layers of the arachnoid membrane* *These cysts can occur anywhere in the brain* 2. Mega cisterna magna
44
What are Choroid plexus cysts?
Cysts in the choroid plexus
45
When does CPCs disappear?
2nd trimester
46
What is CPC associated with?
Trisomy 18
47
What is the variation of incidence with T18 for CPC?
1 in 200 CPCs are associated with trisomy 18
48
One cause for Dolichocephaly is what?
Breech baby
49
What is the calculation for Cephalic index?
BPD / OFD and should be <75
50
What are craniosynotoses?
Bizarre fusion of the cranial sutures
51
What does craniosynostoses look like? Why?
Cloverleaf - all sutures fuse before the brain is finished growing
52
If the view of the brain is especially clear, you should consider what? 2
1. Conditions which have poor mineralization 2. Also, can the brain be compressed with slight pressure?
53
In osteogenesis imperfect and hypophosphatasia, the cranial bones are what?
Not ossified and the brain can easily be compressed
54
What is a acrania? How many children are affected?
1. Absent cranium 2. 1/1000 births
55
What is anencephaly?
No cerebral cortex - absent or destroyed
56
What is exencephaly? 3
1. Some cerebral cortex, but is abnormal 2. Brain tissue exposed to amniotic fluid damages the brain tissue 3. May be early stage of anencephaly
57
On ultrasound, what does anencephaly look like? 3
1. The facial structures and orbits are present 2. No skull above the orbits 3. Frog look
58
When can anencephaly be diagnosed? (weeks)
12-13 weeks
59
What is the prognosis of anencephaly?
Fatal
60
What are some DDX for anencephaly? 2
1. Amniotic band syndrome 2. Large encephalocele
61
What do we look for with amniotic band syndrome? 3
1. Look for other amputations 2. Waving membrane 3. Watch to see if fetus seems stuck to side wall
62
What would we look for with encephalocele?
Any sign of cranial bones
63
What is an encephalocele?
Herniation of intracranial structures through a defect in the cranium
64
What may encephaloceles contain? 2
1. Only meninges 2. Brain tissue also
65
Most encephaloceles occurs where?
In the midline of the occiput, but can occur anywhere.
66
If encephaloceles occur in the nasal area what might happen?
It might be difficult to see
67
What lab value is affected by encephaloceles?
AFP is increased
68
Can encephaloceles be isolated?
Yes
69
What is Meckel- Gruber syndrome? (how lethal and if it a dominant or recessive condition)
An autosomal recessive lethal condition
70
Encephalocele is often seen with what syndrome? What are signs? 3
Meckel- Bruner syndrome Signs include 1. encephalocele 2. Cystic renal dysplasia 3. Polydactyly
71
What does this image demonstrate?
Meckel-Gruber syndrome
72
What is the sonographic appearance of encephalocele if only meninges protruding? 2
1. Cystic structure with thin membrane 2. Cranial defect present
73
What does encephaloceles look like if the brain is protruding? 2
1. Encapsulated echogenic mass, with cystic areas 2. Cranial defect Present
74
In terms of encephalocele, hydrocephalus occur due to what?
CSF blockage
75
What does this image demonstrate?
Encephalocele
76
What does this image demonstrate?
Encephalocele
77
What does this image demonstrate?
Large encephalocele
78
What is the DDX for a encephalocele? 2
1. Cystic hygroma 2. Teratoma
79
In terms of a cystic hygroma, what should we see in a encephalocele?
Should see septations in cystic area with hygromas
80
What does the prognosis for encephaloceles depend on? 3
Depends on 1. Size of the defect 2. Amount of the brain tissue involve d 3. Whether or not it is associated with Meckel-Bruner syndrome
81
What are arachnoid cysts?
Are fluid filled collections in the layers of the arachnoid membrane
82
Where can arachnoid cysts occur?
Anywhere in the cranium
83
Arachnoid cysts are associated with what?
Nothing
84
On u/s we see what in terms of arachnoid cysts? What might it demonstrate? 2
1. Well defined cyst in brain 2. May demonstrate mass affect
85
What does this demonstrate?
Arachnoid cyst
86
What is the DDX for arachnoid cysts? 2
1. Dandy walker variant if in posterior fossa 2. Porencephalic cysts
87
What is the prognosis for arachnoid cysts?
Is good as long as the cyst does not destroy too much brain tissue or block ventricles
88
When does porencephalic cysts occur?
When brain tissue is destroyed by hemorrhage or an infarct
89
What are some things we see with porencephalic cysts look on U/S? 3
1. Destroyed brain tissue becomes cystic 2. Periventricular halo (close to lateral ventricles) 3. May or May to communicate with ventricles
90
What is the DDX for porencephalic cysts in a neonate? 3
1. Dandywalker malformation 2. Arachnoid cyst 3. Hydrocephaly if it communicates
91
What is the prognosis for porencephalic cysts in a neonate?
Depends on the degree of brain destruction
92
What is hydranencephaly? What is still intact?
1. Variable absence of cerebellum, or destruction of brain tissue 2. Intact cranial vault and meninges
93
What is the most severe form of porencephalic?
Hydranencephaly
94
What causes hydranencephaly? 3
1. Occlusion of ICA 2. Infection or hemorrhage 3. Destruction and resorption of brain matter
95
How common is hydranencephaly?
Rare
96
What does hydranencephaly look like sonographically? 3
1. Intact thalami which are never fused and brain stem 2. May or may not have intact Falx cerebri 3. Irregular brain matter at periphery
97
What is the DDX for Hydranencephaly? 2
1. Severe hydrocephalus (smooth along periphery of cranium) 2. Alobar holoprosecencephaly (would have fused thalami)
98
Wha this the prognosis for Hydranencephaly?
Fatal
99
What is schizencephaly? 2
1. Symmetrical clefts in the parietal or temporal lobes that extend from the ventricles to the cortical surface 2. Brain is split into anterior and posterior segments of the brain
100
What is a lissencephaly? 2
1. Smooth brain 2. No sulcus or gyro due to abnormal migration of neurons from the germinal matrix
101
When can we do a DX for lissencephaly?
Not possible until 3rd trimester
102
What is Microcephaly?
Disproportionally small head compared to the gestation age and abdominal circumference
103
What would classify the head as below 5th%
>3 standard deviations below the mean head
104
When would microscephaly be seen?
Late pregnancy
105
What does Microcephaly implies?
Failure of brain development
106
In terms of Microcephaly, ventriculomegaly occurs due to what?
Less brain tissue
107
The profile of Microcephaly demonstrates what?
Sloping forehead
108
What is Microcephaly associated with?
Many other developmental abnormalities
109
Microcephaly results from what? 5
1. Asphyxia - low oxygen 2. Infections 3. Drugs 4. Alcohol 5. Irradiation
110
The corpus callosum starts to develop at how many weeks? And is not complete until when?
1. 12 weeks 2. 20 weeks
111
What is the corpus callosum?
A bridge of white matter nerve fibres that connects the right and left cerebral hemispheres
112
How does the corpus callosum develop?
From anterior to posterior
113
Abscess of the corpus callosum may be complete or partial? Is it developmental or acquired?
1. Complete or partial 2. Developmental or acquired
114
What would development mean in terms of corpus callosum?
Interruption of formation
115
What does an acquired abscess mean in terms of corpus callosum?
Insults which cause secondary atrophy of previously devoted parts
116
Can agenesis of the corpus callosum be isolated?
Yes
117
What is agenesis of the corpus callosum often associated with? 2
Other CNS abnormalities such as 1. Gerald dysplasia 2. Dandy walker malformation *also associated with anomalies of the face limbs and genitourinary system*
118
What does agenesis of corpus callosum look like sonographically? 2
1. Absence of CSP is your first clue 2. Colpocephaly
119
What is colpocephaly? 2
Lateral ventricles are teardrop shaped 1. Pointed anterior horns 2. Enlargement of the occipital horns only
120
If ACC is suspected what do we do? 2
1. Profile image, try to image from the top of the head in the midline sagittal plane 2. Try EV if fetal head is low in pelvis
121
Where does the Corpus callosum sit?
Superior to the cavum septi pellucidi
122
If ACC is suspected, and if the CSP is absent the 3rd vent will be what?
Elevated or high riding in the head
123
What is the prognosis of ACC? 2 (agenesis of the corpus callosum)
1. If isolated and partial, it may not affect function at all 2. Severity of decreased intellect depends on associated CNS abnormalities
124
What does TORCH stand for?
1. Toxoplasmosis 2. Rubella 3. Cytomegalovirus (CMV) 4. Herpes simplex virus
125
TORCH can cross the placenta and cause what? Followed by what? 3
Encephalitis followed by 1. Microcephaly 2. Ventriculomegaly 3. Calcifications
126
What is toxoplasmosis due to? 2
1. Contact with raw meat 2. Cats, especially kitty litter
127
CMV is common in what situations?
Large populations
128
Herpes can be transplacentally acquired but more commonly due to what?
Vaginal delivery with herpes infection
129
What is the sonographic appearance of TORCH? 6
1. Look for signs of heart failure (enlarged heart) 2. Pleural effusions 3. Ascites 4. Hepatosplenomegaly 5. Hepatic calcifications 6. Echogenic (calcified) Bowel
130
What is the vein of Galen aneurysm?
A variety of Arteriovenous (AV) malformations drain into the vein of Galen and result in its distension as a single dilated midline fluid collection
131
Vein of Galen aneurysm dilation does not occur until which trimester?
The 3rd trimester
132
What does the vein of Galen look like sonographically? How does the neck vessels appear? What does the heart show?
1. Dilated midline collection posterior to the thalamus and mid brain, between the posterior horns of the lateral ventricles 2. Neck vessels may appear prominent 3. Signs of heart failure (cardiomyopathy due to shifting)
133
How can we easily DX Vein of Galen?
Colour doppler
134
What is the DDX for vein of Galen? 2
1. Arachnoid cysts 2. Porencephalic cyst
135
What is the prognosis of vein of Galen?
Poor unless all anastomoses can be cauterize
136
Congenital brain tumors are how common?
Rare
137
What is the most common lesion of the brain?
Teratoma
138
What are Teratomas?
Large echogenic masses with cystic spaces and occasional calcifications
139
What is the prognosis for tumours in the brain?
Dismal
140
What is holoprosencephaly? 2
1. Severe abnormality of the forebrain cleavage (cerebrum or prosencephalon) 2. Fusion of the cerebral hemispheres and thalami
141
What is holoprosencephaly associated with?
T13
142
What are the three classifications of holoprosencephaly?
1. Lobar - mild 2. Semilobar 3. Alobar - severe
143
What is a lobar holoprosencepahly?
1. Fused anterior horns that are squared off 2. Incomplete Falx but 3rd ventricle may be seen
144
What is the semilobar version of holoprosencephaly? 2
1. Single horseshoe shaped ventricle with brain mantle 2. No 3rd ventricle of Falx
145
What is the Alobar version of Holoprosencephaly? 3
1. Little or no corticosteroids mantle 2. Single horseshoe shaped ventricle 3. Fused thalami and no 3rd ventricle or Falx

DMST 315 OBGYN 3 (21 decks)

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