Class 18: Fetal Skeleton Anomalies Flashcards
another name for skeletal dysplasia?
osteochondro dysplasia
define osteochondro dysplasia
abnormal development of cartilage & bones
incidence of skeletal dysplasias are common. T/F?
false
3 associations with osteochondro dysplasia?
- polyhydramnios
- fetal hydrops
- decreased fetal activity with lethal types
skeletal dysplasias are always seen with US. T/F?
false
when do signs of skeletal dysplasia usually manifest?
late 2nd trimester
skeletal dysplasias may not be severe enough to be detected. T/F?
true
what should the sonographer document when assessing fetal limbs? (4)
- existence
- length
- position
- ossification
how to evaluate skeletal dysplasia on US (7)
- limb shortening
- bone contour
- degree of ossification
- thoracic circumference & shape
- hand & foot anomalies
- face & face profile
- other associated anomalies
what is rhizomelia?
shortened proximal extremity (humerus & femurs)
what is mesomelia?
middle limb segment shortened (radius, ulna, tibia, fibula)
what is acromelia?
distal extremity shortening (phalanges & metacarpals)
what is micromelia?
shortening of entire extremity
what is amelia?
absence of entire extremity
what is the most common lethal skeletal dysplasia?
thanatophoric dysplasia
what is the cause of thanatophoric dysplasia?
unknown
5 characteristics of thanatophoric dysplasia?
- very flat vertebral bodies
- extreme micromelia, especially rhizomelia
- telephone receiver long bones
- narrow thorax
- champagne cork app
the following abnormalities are associated with which dysplasia?
- macrocephaly
- frontal bossing
- horseshoe kidney
- imperforate anus
- atrial septal defects
- cloverleaf skull
- massive polyhydramnios
thanatophoric dysplasia
characteristics of type 1 thanatophoric dysplasia?
short & curved femur
flat vertebral bodies
characteristics of type 2 thanatophoric dysplasia?
short & straight femur
flat vertebral bodies
craniosynostosis –> cloverleaf skull
achondrogenesis is a lethal form of dysplasia. T/F?
true
cause of achondrogenesis
CARTILAGE abnl –> abnl bone formation & hypomineralization
what characteristics of achondrogenesis differentiates it from thanotophoric dysplasia?
short trunk & hypomineralization
characteristics of type 1 achondrogenesis
- autosomal recessive
- hypomineralization of BOTH skull & vertebral bodies
- fractures
characteristics of type 2 achondrogenesis
- spontaneous with autosomal mutation
- hypomineralization of only vertebral bodies
- no fractures
what is the most common nonlethal dwarfism?
achondroplasia
achondroplasia is autosomal recessive or spontaneous. T/F?
false – it’s autosomal dominant or spontaneous
the following are characteristics of which skeletal dysplasia?
- frontal bossing
- rhizomelic limb bowing
- trident finger configuration
- possible macrocephaly or hydrocephaly
achondroplasia
what is osteogenesis imperfecta?
bones are abnormally fragile due to hypomineralization of the ENTIRE skeleton; many bone fractures & deformities
what is the cause of osteogenesis imperfecta?
too little or poor quality collagen
what is type 1 osteogenesis imperfecta?
mild – normal life expectancy
fractures after birth
fragile bones & loose joints
growth deficiency
autosomal dominant
what is type 2 osteogenesis imperfecta?
lethal – long bone & rib fractures
hypomineralization in US
which type of osteogenesis imperfecta is seen in US?
only type 2
what is type 3 osteogenesis imperfecta?
handicap type – bones progressively deform throughout life
fractures at birth or when starting to walk
autosomal dominant/recessive
what is type 4 osteogenesis imperfecta?
mildest type – bones fracture easier than normal
short stature
another name for camptomelic dysplasia?
campomelic dysplasia
is campomelic dysplasia lethal?
yes
how common is campomelic dysplasia?
rare
the following are characteristics of what dysplasia?
- shortened & bowed long bones of legs (especially tibia & fibula)
- narrow chest
- large calvarium with small face
- hypoplastic scapulae
- clubfoot
camptomelic dysplasia
where can polydactyly be found?
lateral or medial side of extremity
possible associations with polydactyly?
- trisomy 13, 18, 21
- ellis van-creveld syndrome
- rubenstein-taybi syndrome
what is holt-oram syndrome?
condition with no thumbs
2 associations with holt-oram syndrome
- congenital abnormalities of the heart
- phocomelia of upper limbs
what is phocomelia?
proximal portion of extremities are absent or hypoplastic
VACTERL associations are more commonly found in which patient?
diabetic mothers
what is talipes equinovarus?
clubfoot – median deviation of the sole of foot
5 possible associations for clubfoot?
- genetic syndrome (tri 18)
- spina bifida
- caudal regression syndrome
- muscular dystrophy
- oligohydramnios
what is caudal regression syndrome?
a range of malformations of the caudal end of the neural tube, leading to underdeveloped/agenesis of coccyx area
single umbilical artery may be associated with caudal regression syndrome. T/F?
true
what type of twinning may be associated with caudal regression syndrome?
monozygotic
which drug is associated with caudal regression syndrome?
cocaine
what is sirenomelia?
variable fusion of lower extremities, leading to the mermaid sign on US
3 associations with sirenomelia?
- bilateral renal agenesis
- oligohydramnios
- SUA
