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DMST 315 OBGYN 3 > Fetal Skeletal Dysplasias > Flashcards

Fetal Skeletal Dysplasias Flashcards

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1
Q

Endochondral ossification begins at how many weeks?

A

10 menstrual weeks

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2
Q

What are the first bones to ossify? 5

A
  1. Mandible and maxilla
  2. Clavicle
  3. Calvarium
  4. All long bones
  5. Vertebral laminate
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3
Q

When does the mandible and maxilla finish ossifying?

A

8-19 menstrual weeks

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4
Q

Calvarium is finish ossification when?

A

12-13 weeks

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5
Q

All long bones finish ossification when?

A

End of the 1st trimester

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6
Q

Vertebral laminae finish ossification when?

A

18 weeks

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7
Q

What are some secondary ossification centres?

A

Epiphyses

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8
Q

Secondary ossification centres are separated from the shaft of the long bone by what?

A

A layer of cartilage

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9
Q

Secondary ossification centres develop when?

A

Late in pregnancy and in the neonatal period

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10
Q

What aids in the determination of fetal maturity?

A

Visual aids

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11
Q

When is the distal femur visible?

A

32-35 weeks

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12
Q

When is the distal humorous finished ossifying?

A

> 38 weeks

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13
Q

What might delay secondary ossification centres development?

A

IUGR

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14
Q

Femoral growth is 3mm/week until when?

A

27 weeks

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15
Q

Femoral growth is 1mm/week from when?

A

28 weeks to term

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16
Q

How do we measure the femur?

A

Only the shaft of the femur

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17
Q

Femur is measured as part of what?

A

Part of the anatomy scan and all biometry scans

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18
Q

What is the routine assessment for bones? 8

A
  1. Femur length
  2. Humerus length
  3. Lower limbs
  4. Upper limbs
  5. Foot/Ankle angles
  6. Feet palmer view
  7. Hands
  8. Spine and calvarium
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19
Q

What do we assess for in terms of ossification/ bones? 5

A
  1. Size
  2. Presence
  3. Shape
  4. Contour
  5. Density
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20
Q

What are 3 errors of morphogenetic?

A
  1. Malformation
  2. Deformation
  3. Disruption
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21
Q

What is malformation?

A

Abnormal formation of tissue (genetic and telegenic drugs)

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22
Q

What is deformation?

A

Normally developed, but abnormal force alters structure shape

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23
Q

What is an example of deformation? 2

A
  1. Oligohydraminos causing clubbed feet
  2. Features of potter’s sequence
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24
Q

What is disruption?

A

Normally developed, but abnormal interference causes tissue destruction

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25
What are two examples of disruptions?
1. Vascular occlusion = limb reduction 2. Tearing amniotic membrane = Tissue destruction
26
What is skeletal dysplasia?
The abnormal development of the cartilaginous and osseous tissues, resulting in bones that appear shortened, thin, deformed or that fail to form at all.
27
What is another name of skeletal dysplasia?
Osteochondrodysplaisa
28
What are indications of skeletal dysplasia? 4
1. Specific genetic risks (Previous pregnancy, family history) 2. Apparent limb abnormality 3. Associated abnormality 4. Abnormal amniotic fluid
29
What does family history of skeletal dysplasia warrant?
Extensive screening of target areas
30
Extensive screening for skeletal dysplasia can help identify what?
The types of skeletal dysplasia as many disorders inherit as AR or AD
31
What is consanguinity?
Couples that are relatives
32
What presents from consanguinity?
AR traits more prevalent
33
What are four patterns of limb shortening?
1. Rhizomelia 2. Mesomeilia 3. Mircomeilia 4. Acromeilia
34
What is rhizomelia?
Proximal portion of limb is shortened (fever and humerus)
35
What is mesomelia?
Middle portion of limb is shortened (Radius/ ulna and tibia/fibula)
36
What is micromelia?
All portions of the limb are shortened
37
What is acromelia?
Distal portion of limb (hands/ feat)
38
What is phocomeilia? 2
1. Abscesses of the proximal portion of the extremity 2. Hands or feet attached to trunk of the body
39
What does phocomelia resemble ?
Presemnil flipper
40
Shortened long bones are routinely measured when?
FL and HL at detailed scan
41
What is the routine for measurements of FL and HL at detailed scan? 4
1. Cross-reference to BPD/long bone chart 2. Marker is <0.9 of expected) 3. Or <5% 4. 2 SD for fetal age
42
In terms of shortened long bones, once a skeletal abnormality is identified, what happens to the long bones.
Once a skeletal abnormalities is identified, all bones should be measured
43
What classifies as severely shortend long bones?
>4 standard deviation
44
If the bones are -2-4 SD, what needs to be done?
F/U in 3-4 weeks to ensure normal growth
45
In terms of shortened bones, when can we expected normal lengths?
1. Normal lengths early in 2nd trimester
46
Dysplasia’s that manifest later mean what?
Less severe features that have a better prognosis
47
What is another name for sporadic dominant?
AR inherithence pattern
48
What are some common lethal skeletal dysplasia? 3
1. Thanathorphic dysplasia a 2. Achonoderognesis 3. Osteogenesis imperfects II
49
What are some rare lethal skeletal dysplasias? 3
1. Congenital hypophophastasia 2. Camptomelic dysplasia 3. Homozygous achondroplasia
50
There are how many different types of skeletal dysplasia
436
51
What does this image represent?
Patterns of limb shortening
52
What does this image represent?
Phocomelia
53
What are some common lethal dysplasia’s? 3
1. Thanatophoric dysplasia 2. Achondrogenesis 3. Osteogenesis imperfects
54
60% of common lethal dysplasia’s are what? 2
1. Thanatophoric 2. Achondrogenesis
55
Dysplasia’s are considered lethal with what? 2
1. Decreased thoracic circumference 2. Severe micromelia
56
What does decreased thoracic circumference do with lethality?
It causes pulmonary hypoplasia
57
What do we need to determine thoracic circumference and lethality? 2
1. Compare chest and abdomen 2. Compare femur length and abdomen
58
What is abnormal narrow chest ratios? 2
1. Chest/ Abdoment ratio <0.79 2. FL/AC <0.6 *Indicative of hyperplasticity thorax*
59
Thanatophoric means what in Greek?
Death bearing
60
What is the most common lethal skeletal dysplasia?
Thanatophoric dysplasia
61
Thanatophoric dysplasia is believed to be autosomal what? Why?
Dominant, because it is caused by mutations of the FGFR3 gene
62
What is the FGFR3 gene?
Fibroblast growth factor receptor
63
In terms of Thanatophoric dysplasia, around 50% present how?
Clinically as large for gestational age (LGA) due to polyhydraminos
64
What are some general abnormalities of Thanatophoric dysplasia? 7
1. **Micromelia** 2. Redundant skin folds 3. Clover leaf skull deformity (**Kleeblattschadel**) 4. Frontal bossing 5. Bowed limbs (Telephone receiver) 6. **Narrow thorax** 7. Platyspondyly
65
What is Platyspondyly? 2
1. Flatness of the vertebral bodies 2. Thin vertebrae bodies
66
What is seen with TD type 1? 4
1. Extreme rhizomelia 2. Bowed bones 3. Platyspondyly 4. Frontal bossing
67
What is seen with TD type 2? 3
1. Straighter long bones 2. Taller vertebral bodies 3. Kleeblattschadel
68
Between TD Type 1 and 2 which is more common?
Type 1
69
If the vertebral bodies appear flattened or less than the intervertebral space, what has happened?
Platyspondyly
70
How do we find the expected FL?
Check the BPD to the expected FL
71
What is the second most common lethal skeletal dysplasia?
Achondrogenesis
72
What is Achondrogenesis?
Decreased mineralization
73
How many variations of Achondrogenesis are there?
There are 2. Type 1 and 2
74
What is the occurrence rate of type 1 Achondrogenesis?
20%
75
What is the most severe form of Achondrogenesis?
Type 1
76
Type 1 Achondrogenesis is autosomal what?
Recessive
77
What are type 1 Achondrogenesis s/s? 2
1. Abnormal cranial and spinal ossification 2. RIb fractions
78
What is the occurrence rate of type 2 Achondrogenesis?
80%
79
What is the severity of Achondrogenesis type 2?
Less severe then 1
80
Achondrogenesis type 2 is autosomal what?
Dominant
81
What do we see with type 2 Achondrogenesis? 4
1. Abnormal spinal ossifications 2. **Normal cranium** 3. **No rib fractures** 4. Less severe mineralization abnormalities
82
What are some sonographic features of Achondrogenesis? 6
1. **Micromelia** 2. Frontal Bossing and macro Tania 3. **Small thorax** 4. **Decrease mineralization of bones** 5. **Fractures and bowing of limbs** 6. **May exhibit hydrops**
83
What is the chest appearance on U/S with Achondrogenesis?
Small thoracic circumference
84
Osteogenesis imperfecta is Autosomal dominant or recessive?
Either or depending on the type
85
What is osteogenesis imperfecta?
Defective collagen quality or quantity
86
In terms of osteogenesis imperfecta, what does defective collagen quality or quantity lead to? 2
1. Leads to decreased mineralization of bone and bone fragility 2. Results in “Brittle bones”
87
What are the different types of osteogenesis imperfecta?
Type 1-4
88
Which forms of Osteogensis imperfecta are lethal or most severe?
Type 2
89
Which forms of osteogensis imperfecta are mild or non-lethal?
Types 1, 3, and 4
90
What are some S/S with Type 2 osteogenesis Imperfecta? 5
1. **Severe Micromelia** 2. Apparent thickening along the bones from increased calluses, from the **fractures** 3. **Hypomineralization of bones** 4. Rib fracture (Collapsed thoracic cage) 5. Platyspondyly
91
What are three types of lethal skeletal dysplasia? 3
1. Congenital hypophosphatasia 2. Comptomelic dysplasia 3. Homozygous achondroplasia
92
In terms of Congential hypophosphatasia, it is autosomal what/
Recessive
93
What is congenital hypophosphatasia?
Abnormal bone mineralization (alkaline phosphatase deficiency)
94
What are some features of congenital hypophosphatasia? 4
1. Variable micromelia 2. Diffuse hypomineraliztion 3. Bones are thinned, delicate or absent 4. +/- fractures
95
What can congenital hypophosphatasia represent if severe?
OI type 2 if severe
96
What is comptomelic dysplasia also known as?
Bent bone dysplasia
97
What are some features of comptomelic dysplasia? 5
1. Bowing of most long bones 2. No fractures 3. Severe talipes equinovarus (club feet) 4. Absent/ hypoplastic scapulas 5. Narrow thorax
98
What must happen for the baby to have homozygous achondroplasia?
One parent must be affected but usually its both parents.
99
What are some features seen with Homozygous achondroplasia? 3
1. Rhizomelia 2. **Small Thorax** 3. Large cranium
100
What are three non-lethal skeletal abnormalities?
1. Heterozygous achondroplasia 2. Asphyxiating thoracic dysplasia 3. Ellis-van crevled syndrome
101
What is the most common non lethal dysplasia?
Heterozygous achondroplasia
102
What kind of new mutation can heterozygous achondroplasia be?
Autosomal dominant
103
Is there any decrease in lifespan and intellect of heterozygous achondroplasia?
Normal life and intellect
104
What are some features of heterozygous achondroplasia? 5
1. **Moderate rhizomelia - late onset** 2. **Noticed in 3rd trimester (femurs)** 3. Large calvarium 4. Frontal bossing 5. **normal thorax**
105
What is asphyxiating thoracic dysplasia also known as?
Jeune syndrome
106
What are some S/S of asphyxiating thoracic dysplasia? 3
1. **Thorax long and narrow** 2. **Polydactyly** 3. **Pelvic/ Renal anomalies**
107
What are some treatments of asphyxiating thoracic dysplasia?
Undergo corrective surgery for thoracic expansion
108
What is Ellis-van creveld syndrome also known as?
Chondroectodermal dysplasia
109
How common is Ellis-van creveld syndrome?
Rare
110
Ellis-van creveld syndrome is autosomal what?
Recessive
111
Where is Ellis-Van Creveld syndrome found?
Frequently found in small communities where consanguineous couples may be common
112
What are some things seen with Ellis-Van Creveld syndrome? 7
1. Short limbs 2. Short ribs 3. Narrow thorax 4. Polydactyly 5. Dysplastic nails and teeth 6. Upper lip abnormalities 7. Congenital heart disease
113
Aase syndrome is autosomal what?
Recessive
114
What is Aase syndrome?
Underdevelopment of bone marrow causing anemia
115
What are s/s of Aase syndrome? 5
1. Congenital limb contractures 2. Cleft palate 3. Ear deformities s 4. Droopy eyelids 5. Triphalangeal thumb
116
What happens to severe cases of Aase syndrome?
Severe cases are mostly stillborn or die early in life
117
Holt- Oram syndrome is autosomal what?
Dominant
118
What kind of s/s are seen what Holt-Oram syndrome? 2
1. Skeletal and cardiac abnormalities 2. Skeletal (radial ray etc.)
119
In terms of Holt-Oram syndrome, cardiac defects determine what?
The severity of the outcome
120
What does TAR syndrome stand for?
Thrombocytopenia- absent radius syndrome
121
TAR syndrome is autosomal what?
Recessive
122
TAR syndrome has what deficiencies? 2
1. Decreased platelets 2. Bilateral absent radii
123
What is the prognosis of TAR syndromes?
Poor due to intracranial hemorrhage
124
What is Radial ray syndrome?
1. Absent or hypoplastic radius 2. Radial deviation of hand and absent hypoplastic thumb
125
What are some anomalies that we can see radial ray with? 5
1. T18 2. Holt- Oram syndrome 3. Roberts syndrome 4. VACTERL 5. TAR syndrome
126
What is Talopes equinovarus?
Medial deviation and inversion of the sole of the foot
127
What is Talipes equinovarus known as?
Club foot
128
What is talipes equinovarus caused by? 4
1. Chromosomal 2. NTD 3. Skeletal dysplasia’s 4. Decreased fluid
129
What is an rocker bottom foot?
Prominent heel with absent arch (convex sole) due to large calcaneus
130
What are some focal limb abnormalities? 7
1. Polydactyly 2. Olgiodactyly 3. Syndactyly 4. Brachydactyly 5. Clinodactyly 6. Hitchhikers thumb 7. Talipomanus (club hand)
131
What is Preaxial Polydactyly?
Focal limb abnormalities locales on the radial or tibial side
132
What is post axial Polydactyly?
If the extra digits are on the ulnar or fibulae side
133
What is brachydactyly?
Marked shortening of the hand digits with trident (pitch fork) configuration in homozygous achondroplasia
134
What is talipomanus?
Club hand
135
What does Amelia mean?
Absence of one or more limbs
136
What does hemimelia mean?
Absence of one or more extremities below the elbow or knee
137
What does ascheria mean?
Absence of one or more hands
138
What does aporia mean?
Absence of one or more feet
139
What is adactyly?
Absence of one or more digits from the hands or feet
140
What is meromelia?
Absence of part of a limb
141
What is ectrodactyly?
Split hand or split foot (Lobster claw)
142
Amniotic band syndrome results from what?
1st trimester rupture of amnion
143
Amniotic bands extends from where?
Chorionic surface to fetal tissue
144
What does Amniotic band syndrome result in? 3
1. Limb constriction 2. Clefting 3. Amputation
145
What is contracture?
Shortening/tightening of muscles and tendons that cause joints to shorten and stiffen
146
What is arthrogryoposis?
Joint contracture in two or more different areas of the body
147
Contracture is usually caused by what?
Reduced fetal movements
148
What are 5 various causes of contracture?
1. CNS abnormalities 2. Genetic syndromes 3. Fetal environment 4. Skeletal dysplasia 5. Maternal infections
149
What do we assess for dysplasia? 10
1. Length of all long bones 2. Shape, contour, and density of all bones 3. Spine (curvature and density) 4. Skull 5. Face 6. Head size, shape, and ventricle 7. Thoracic circumference and shape are well as cardiac circumference 8. Hands and feet 9. Skin folds, thickness 10. Amniotic fluid
150
What is useful to assess bone density, mineralization and vertebral bod shape
Radiograph
151
Why do we measure the foot length?
The fetal foot will be a more accurate measurement for gestation age in the case of a skeletal dysplasia
152
Some skeletal dysplasia’s do not impair the growth of what?
The fetal feet
153
A comparison of the what can assist in the diagnosis of a skeletal dysplasia
Long bones to fetal feet
154
Careful assessment of skeletal dysplasias enables what? 2
1. Accurate assessment of prognosis in 85% of dwarfism 2. Enable accurate diagnosis of a specific skeletal dysplasia in about 50% of cases
155
If the thorax is abnormally small what is the prognosis?
Poor
156
What re 5 abnormalities that will be seen with small thorax?
1. Thanatophoric dysplasia 2. Achondrogenesis 3. Osteogenesis imperfecta 4. Congenital hypophosphatasia 5. Camptomelic dysplasia
157
What is more important than determining the specific dysplasia?
Determining lethal vs non- lethal disease
158
Increase risk of lethal dysplasia if we see what? 5
1. Severe micromelia (>4 SD below mean) 2. **Decrease thorax <5th percentile** 3. Decreased bone density 4. Long bone fractures 5. Kleeblattschadel
159
What does this image represent?
1. normal 2. Rhizomelic 3. Mesomelic 4. Severe micromelic
160
What does this image represent?
Phocomelia
161
What does this image represent?
Narrow chest
162
What does this image represent?
Front bossing and Kleeblattschadel
163
What does this image represent?
Craniosynotosis Kleeblattschadel
164
What does this image represent?
Normal vs Platspondyly
165
What does this image represent?
Platyspondyly
166
What does this image represent?
Frontal bossing
167
What does this image represent?
Achondrogenesis
168
What does this image represent?
Decreased mineralization
169
What does this image represent?
Camptomelic Dysplasia
170
What does this image represent?
Short ribs
171
What does this image represent?
Radial ray
172
What does this image represent?
Talipes equinovarus
173
What does this image represent?
Talipes equinovarus
174
What does this image represent?
Rocker bottom feet
175
What does this image represent?
1. Missing middle finger 2. Fused fingers
176
What does this image represent?
Polydactyly feet or hand s
177
What’s happening here ?
Talipomanus (Club hand)
178
What does this image represent?
Amniotic band syndrome

DMST 315 OBGYN 3 (21 decks)

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