Osteogenesis Imperfecta Flashcards
What is osteogenesis imperfecta?
Genetic disorder – several subtypes
Usually autosomal dominant (Types I-IV)
Can be autosomal recessive (Types VII, VIII – identified in 2006)
Other types non-specific genetics. Can be spontaneous mutation
osteogenesis imperfecta is what kind of disease?
Connective tissue disease
Impaired Type I collagen synthesis (skeleton, organ systems)
1:10,000-20,000 individuals
No racial, ethnic patterns of inheritance
Equal boys and girls
summary of histological bone abnormalities
- bone has a smaller than normal external size (bone thickness) because of sluggish periostea bone formation
- trebeculae are reduced in number and are abnormally thin
- although individual osteoblasts produce less bone than norma, the overall bone formation rate in the trebecular compartment is amplified
- increase does not lead to a net gain in trabecular bone bc bone resorption is also enhanced
OI Wynne-Davis Sillence Types
Type I: Mild form, AD
Type II: Most severe, lethal, AD
Type III: Most severe compatible with life, AD
Type IV: Heterogeneous, AD &AR. Source of new types
Sillence Type I
- autosomal dominant
- blue sclerae
- mild shortening
OI Lethal - Sillence Type II
- uncommon
- autosomal dominant
- intrauterine or infantile death
Type III
- Autosomal Dominant
- Blue to white sclera
- sibling involvement
OI Sporadic - Type IV
- Common
- Autosomal Dominant
- Blue to white sclera
- Intermediate severity
- stature moderate to severe shortening
- Many different subtypes
mechanism of spinal deformity in OI
inability to withstand compressive load
spinal deformity in OI
- inability to withstand compressive loads
- Vertebral Fractures/ compression fractures bc of decreased BMD
- Ligamentous Laxity
- Loss of Mechanical Stability
- Earlier onset
- Poor response to corrective
- Braces or surgery
- Progression independent of growth
Incidence in Scoliosis by type
- I: 39%
- II: 0%
- III: 68%
- IV: 54%
hypertrophic callus
kids develop fever, increased leukocytes
- common post op treatment to address callus formation
signs and symptoms
- fractures
- skeletal abnormalities
- muscle weakness
- ligamentous laxity: can be hypo or hyper mobile
- dentition: poor growth formation of teeth, structurally weak, discoloration
- hearing: bones in our ears
- sclera: collagen here too so we see that gray/blue tint
What is the hallmark sign?
bowing of long bones
Rarely have…
COG problems
fractures
- can have tons as they are developing
- rate of fractures decrease with puberty
- healing time is equal to normal people
- callous formation is abnormal
OI fracture assessment and statistical model
- to find how much we can stress/load these kids to help them but not cause fractures
- clinical assessments + Nonotek to assess cortical/trabecular bone properties + motion analysis + muscle loads + finite element analysis
How is spinal deformity different than other scoliosis?
- earlier onset
- poor response to corrective braces/surgery
- progression independent to growth
- spondylolisthesis happens too
Basilar Invagination
- kids have larger heads and shorter trunks so foramen magnum is bigger
- this plus ligamentous laxity can cause cerebellum type herniation
- something to watch for if they start to show UMN signs
more distal weakness
- especially PF
weakness effect on gait
- more time in double limb support
- gait speed is reduced
- more time in stance phase than swing phase
- tend to have an overall more “cautious” gait pattern prioritizing stability over mobility
- more lig laxity = more knee hypertext during midstance
- decrease in overall PF during pushoff
- lack of ability to generate power @ ankle
Foot pressure analysis
- COP should change throughout stance
- severe valgus –> 70% of stance is spent loading the mid foot instead of a progressive hindfoot–> midfoot –> forefoot
- more contact pressure @ midfoot + more collapse of plantar aponeurosis + medial longitudinal arch
- load the midfoot more medially too/valgus loading
Medial mangement
- nutrition
- meds: most not great, pamidronate biphosphates may decrease bone resorption + increase BMD
- ANY interventions have to maximize opportunity to increase BMD so bones can withstand more stresses before failure
- Bracing
- Surgery
Bracing
- useful to provide support and correct alignment –> bowing of long bones and decrease pain
- we want to improve ADLs and time spent upright to promote WB
- but putting brace on causes immobilization so that can decrease bone density
- balance is hard
surgery
- intermedullary rods = stabilize fracture –> want better alignment so then WE can put them in WBing to load the bones with less fear of fracture
fracture –>
immobilization –> osteoporosis –> fracture
bad bad bad
3 rehab issues
- decreased CV fitness
- msk deformity and fragility
- functional limitations –> depends on type
decreased CV fitness
- change in thorax –> vertebral fx –> short thorax –> ribs horizontal so cant get thorax to expand to get air in
- kyphotic/scoliotic
- thoracic stiffness
- vascular changes –> decrease BP (probs bc vessels are lax)
- inactivity
muscular deformity and fragility
- fractures and poor healing
- limb length deficiency
- ROM –> in type one: decreases over time; in type 3 &4: more severe limitations + doesnt progress
functional limitations: Type I
- PEDI increases over time; similar to typically developing
functional limitations: Type III and IV
- functional abilities DO improve
- need for parental assistance decreases
- dont get tot typically developing but we can help a lot w/ teen and compensatory strategies to get them more independent
- very smart
Pt management – sites for PT delivery
- everywhere –> we have capacity to maximize participation in lots of areas
- in clinic: manage orthotics; acute rehab post op or injury
- EI and school: dont really need special ed; functional training, gait training, exercise
Focus for PT intervention
- participation
- improve function
- improve ROM to improve alignment
- improve mm strength in trunk and extremities to improve alignment
things you need to be more aware of in babies with OI
- high fracture risk
- parent training
- handeling
- positioning
- normal development may be delayed bc of weakness and skeletal abnormalities
handling babies with OI
- want to support extremities when carrying
- do not lift by feet!! change diapers with log rolling technique
- avoid pushing, pulling, twisting extremities
positioning for babies with OI
- goal is to support extremities
- add padding/shock absorption to surfaces
signs and symptoms of fractures in babies with OI
- crying
- hypersensitive to touch
- unwilling to move extremity
- palpation to redness/heat/discoloration
special issues in toddlers and preschool
- focusing on independent mobility
- gait training just gotta think of safety considerations
- promote WBing to stimulate bone growth (standing programs)
special issues in children
- fracture rate may decrease as approaching puberty
- post IM rod surgery –> watch for signs of rod slipping
- this is the time kids get a lot of corrective surgeries
signs of rod slipping
- change in limb orientation
- change in length of limb
- bruising
- bump at end of bone
special issues in teens
- weight control –> more weight = harder to move and participate in activity
- change in body proportions = changes in ADL performant and effort of movement
- working on functional independence and aerobic exercise
lifespan considerations
- moms with OI
- pregnancy changes, birthing, motherhood, probs gonna need C section
- adult ortho, PF training
