Osteogenesis Imperfecta

what is osteogenesis imperfecta known as

brittle bone disease

osteogenesis imperfecta

disorder of collagen synthesis leads to recurrent fractures + deformation

what is the incidence of osteogenesis imperfecta

equal among males/females + racial/ethnic groups

what is the etiology of osteogenesis imperfecta

most inherit from parent (autosomal dominant inheritance)

what is the pathophysiology of osteogenesis imperfecta

due to defect in collagen synthesis

- mutated gene instructs body to make either:
1. too little type 1 collagen
2. abnormal polypeptide chains that can't form triple helix of type 1 collagen

6 diagnostic tools for osteogenesis imperfecta

1. DNA testing
2. prenatal ultrasound: after 15 wks gestation to identify fractures
3. fetal 3D CT scan
4. human chorionic villus biopsy (takes piece of placenta at 14-20 wks gestation to determine if a child has defect)
5. DEXA (low bone mineral density)
6. X-ray films
- multiple old fractures
- skele deformities
- long bones w/ thin radiolucent appearance
- malformed ribs

osteogenesis imperfecta type I

most common form + mildest clinically
- 2 types: A + B

what type of osteogenesis imperfecta is most common + mildest clinically*

type 1

2 types of osteogenesis imperfecta typeI

type A: teeth are normal
type B: dentinogenesis imperfecta is a feature (abnormal tooth development)

6 clinical manifestations of osteogenesis imperfecta type I

1. grayish-blue sclerae at birth
2. mild-moderate bone fragility
3. osteopenia
4. mild femoral bowing at birth
5. generalized ligamentous laxity with joint hypermobility
6. hearing loss by teens

osteogenesis imperfecta type II

most severe form
- lethal: mainly due to pulmonary complications from rib + vertebral fractures

what is the most severe form of osteogenesis imperfecta

type II

why is osteogenesis imperfecta type II considered to be lethal

mainly due to pulmonary complications from rib + vertebral fractures

5 clinical manifestations of osteogenesis imperfecta type II

1. severe bone fragility
2. at birth: short limbs, small chests + soft skulls
3. sclerae dark blue or gray
4. intrauterine fractures common
5. respiratory + swallowing problems

osteogenesis imperfecta type III

severe form + usually result of new mutations
- healing is impaired
- lifespan maybe shortened due to respiratory conditions

9 clinical manifestations of osteogenesis imperfecta type III

1. fractures + deformities from utero
2. large skull (upper portion) + triangular face
3. dentinogenesis imperfecta
4. blue to pale blue sclerae
5. severe osteopenia
6. severe disorganization of growth plate structure
7. progressive kyphoscoloiosis
8. early onset of hearing loss
9. very short stature

osteogenesis imperfecta type IV

moderate form
- diagnosis can be made at birth but often occurs later
- normal birth weight + length
- osteopenia occurs with aging
- child might not fracture until walking
- 2 subsets: A + B

2 subsets of osteogenesis imperfecta type IV

A: normal dentition
B: dentinogenesis imperfecta (majority)

7 clinical manifestations of osteogenesis imperfecta type IV

1. slightly gray sclerae
2. moderate bone fragility
3. mild femoral bowing at birth
4. osteopenia occurs with aging
5. scoliosis
6. mild bone angulation
7. child might not fracture until walking

what 2 types of osteogenesis imperfecta are milder + normal lifespan

type I + IV

what type of osteogenesis imperfecta is the most severe + 90% die in first few weeks

type II

what is mortality of osteogenesis imperfecta III related to

cardiorespiratory failure stemming from kyphoscoliotic deformity
- significant risk also exists of basilar invagination of skull + intracranial bleeding

13 general clinical features of osteogenesis imperfecta (slide 1 of clinical features)

1. brittle bones
2. joint hypermobility
3. thin skin
4. weak muscles
5. diffuse osteoporosis
6. shortened stature
7. multiple recurrent fractures
8. blue sclerae
9. deformed teeth
10. deafness
11. hernias
12. easy bruising
13. excessive sweating

6 general clinical features of osteogenesis imperfecta (slide 2 of clinical features)

1. scoliosis
2. pectus deformity

3. metabolic defects
- elevated serum pyrophosphate
- decreased platelet aggregation

4. cardiovascular complications
- aortic + mitral valve insufficiency
- aortic dissection

5. triangular face: type III/IV

6. developmental motor skills often delayed
- due to poorly developed muscles, hypermobility of joints + multiple fxs requiring immobilization

2 goals of medical management for osteogenesis imperfecta

1. manage fractures
2. promote function + independence

fractures of osteogenesis imperfecta

- most heal well
- short-term immobilization
- prevention important
- treatment options: surgery, medications, healthy lifestyle + physical therapy

rodding

metal rod inserted into long bones to control fractures + improve deformities associated with decreased function in OI patients

progressive scoliosis

bracing NOT usually recommended
- force from brace can deform ribs rather than straighten the spine

medication for fractures of osteogenesis imperfecta

bisphosphonate drugs
- slows loss of bone + doesn't build new bone
- reduces long bone fractures/vertebral compression

others researched: growth hormone, stem cell therapies + anti-sclerostin antibody

healthy lifestyle treatment option for fractures of osteogenesis imperfecta

- adequate intake of:
1. calcium (maintain bone density)
2. vitamin C (promote healing)
- avoid smoking, alcohol, caffeine + steroid medications
- genetic counseling

7 roles of PT in osteogenesis imperfecta

1. protective handling + positioning
2. strengthening
3. adaptive equipment
4. ambulation
5. post-surgery
6. aquatics
7. education/prevention

role of PT: ambulation

- type I OI: majority of children ambulate either as functional or household ambulators
> ~50% walk without any type of AD as community ambulators
- children with type III OI: ~1/2 dependent on power mobility, with only 27% becoming household ambulators
- children with type IV: 26% community ambulators + 57% household ambulators
- best predictor of ambulatory status: disease type + ability to sit by 9/10 months of age

role of PT with osteogenesis imperfecta

- always be aware of infant's limbs
- in severely affected babies: use a covered pillow for transporting
- allow infant to explore independent movement
- support infant in many position (allow muscles to develop to aide in sitting + standing down)

role of PT: education

- teach family how to care + handle their newly diagnosed baby
- promote independent function: teach family + patient how to modify home + school environment to accommodate their short stature + low strength
- local support group

what is the DO precautions of osteogenesis imperfecta

lift infant by placing one hand under buttocks + legs and other hand under shoulders, neck + head

5 DO NOT precautions of osteogenesis imperfecta

1. push/pull on a limb
2. lift an infant from under armpit
3. lift an infant by ankles
4. perform activities that will jar or twist spine
5. no bouncy seat