Ch. 65 Flashcards
Skeletal dysplasia
Term used to describe abnormal growth and density of cartilage and bone
Refers to disproportionately short stature
Dwarfism
Dwarfism occurs secondary to
Skeletal dysplasia
True or false
Some skeletal dysplasia are incompatible with life
True
Lethal forms of skeletal dysplasia are _ in prenatal forms
Extremely severe
Non-lethal skeletal dysplasias tend to manifest in __ forms
Milder
When a skeletal dysplasia is suspected the protocol should be to include
- Assess limb shortening
- Assess bone contour
- Estimate degree of ossification
- Evaluate TC and shape
- Survey for coexistence hand and foot anomalies
- Evaluate face and profile
- Survey other associated anomalies
Skeletal dysplasia is suspected when
limb lengths fall more than 2 standard deviations below the mean
Rhizomelia
Shortening of the proximal bone segment (humerus and femur)
Mesomelia
Shortening of the middle segments (radius/ulna and tibia/fibula)
Micromelia
Shortening of the entire extremity
Most common lethal skeletal dysplasia
Thanatophoric dysplasia
Term thanatophoric comes from Greek word _ meaning _
Thanatos
Death personified
Thanatophoric dysplasia Type 1
Short, curved femurs, flat vertebral bodies
Thanatophoric dysplasia Type 2
Short, straight femurs, flat vertebral bodies, cloverleaf skull
Clover leaf skull aka
Kleeblattschadel
Thanatophoric dysplasia: Why do most infants die shortly after birth
Due to pulmonary hypoplasia resulting from a narrow thorax
Sono: thanatophoric dysplasia (10)
Severe micromelia Cloverleaf skull Narrowed thorax w/ shortened ribs Protuberant abdomen Frontal bossing Hypertelorism Flat vertebral bodies (platyspondlyly) Severe polyhydramnios Hydrocephalus Non immune hydrops
Most common non lethal skeletal dysplasia
Achondroplasia
Achondroplasia results from _ which _
decreased endochondral bone formation
produces short, squat bones
Causes of achondroplasia
Most commonly: results from spontaneous mutation
- can be transmitted in autosomal fashion
- advanced paternal age increases the risk
Heterozygous achondroplasia is inherited _
By one parent
Heterozygous achondroplasia has _ survivable rates
Good
Intelligence and life span of heterozygous achondroplasia
Normal
Health problems that may be included with heterozygous achondroplasia are _ and may require _
Neurological complications
May require orthopedic of neurological surgical intervention
Homozygous achondroplasia is inherited by
2 parents
Homozygous achondroplasia is (mortality)
Lethal
Most infants die shortly after birth
Why do most infants with homozygous achondroplasia die shortly after birth
Respiratory complications
With homozygous achondroplasia the thorax is
Narrow
Sono achondroplasia
o Rhizomelia o macrocephaly o Trident hands [short proximal & middle phalanges] o Depressed nasal bridge o Frontalbossing o Mild ventriculomegaly
Achondrogenesis
Rare
Caused by cartilage abnormalities which result in abnormal bone formation &
hypomineralization
Achondrogenesis type 1
Most severe
Achondrogenesis type 1 Is transmitted in
Autosomal recessive mode
Achondrogenesis type 2
Less severe
More common
Achondrogenesis type 2 result of
Spontaneous mutation
Achondrogenesis is _ (mortality)
Lethal
Infants either being stillborn or die shortly after birth
Why is achondrogenesis lethal
Pulmonary hypoplasia
Sono achondrogenesis
o Severe micromelia * o Decreased or absent ossification of the spine oMacrocephaly* o Short trunk o Short thorax & short ribs o Micrognathia* o Polyhydramnios o Hydrops possibly identified
Osteogenesis Imperfecta
Rare disorder of collagen leading to brittle bones Manifestation in teeth skin ligaments Blue sclera (blue tint to the whites of the eyes)
Osteogenesis Imperfecta: mildest forms
1 & 4
Osteogenesis Imperfecta: autosomal dominant transmission
Types 1 & 4
Osteogenesis Imperfecta: Transmitted in autosomal-dominant or autosomal-recessive manner
Type 3
Osteogenesis Imperfecta: Most severe/lethal
Type 2
Osteogenesis Imperfecta: Inherited autosomal dominant or autosomal recessive or may result from spontaneous mutation
Type 2
Normal ossification should be done by
18 weeks
Osteogenesis imperfecta:
Prognosis:
Children with type 1 &4
May be short (stature)
Multiple fractures
Osteogenesis imperfecta:
Prognosis:
Type 1
May also suffer from kyphoscoliosis & deafness
Osteogenesis imperfecta:
Prognosis:
Type 3
May produce significant handicaps
Due to the severity of the brittle bones and multiple fracture
Osteogenesis imperfecta:
Prognosis:
Type 2
Die shortly after birth
Due to respiratory complications
Sono: osteogenesis imperfecta
Increased nuchal translucency in the 1st trimester
Compressible skull bones
Multiple fractures leaves bones bowed, thickened, or sharply angulated
Polyhydramnios
Sono: osteogenesis imperfecta specifically type 2
Generalized hypomineralization of bones, especially the skull
Multiple fractures of:
Long bones
Ribs
Spine
▪Narrow thorax
▪Micromelia