Bone pt 2 Flashcards
What are causes of rickets/osteomalacia?
- low vit D
- phosphate deficiency
both cause defects in mineralization
What is x linked hypoP?
most common type of hereditary rickets
FGF23 cant be inactivated - renal P wasting
What is wasted renally in fanconi syndrome?
P, glucose, bicarb, amino acids
If a tumor is causing osteomalacia, what is it secreting? what is the action of this hormone?
paraneoplastic phosphatonins
-inhibit inactivation of FGF23 - renal P wasting
How would you determine rickets vs osteomalacia?
rickets occurs when the growth plate is still open
What is the pathognomonic shape of the epiphysis in rickets?
flared and cup shaped
What are some physical signs of rickets?
- pigeon breast deformity
- frontal bossing - prominent forehead
- rachitic rosary - osteoid deposition on chondrocostal junction
- bowing of the legs
What are the lab findings in osteomalacia /rickets?
- dec serum calcium
- dec serum phosphate
- inc PTH
- inc alkaline phosphatase - inc osteoblast activity
- need alkaline envt to add calcium
What occurs in osteoporosis?
loss of trabecular bone mass - porous bone at risk for fracture
What are the lab values in osteoporosis?
serum values are normal but DEXA scan shows decreased bone density
When does your bone density peak?
age 30
What are two types of osteoporosis?
- estrogen deficient - women
- increased osteoclasts - senile - men and women >70
- decreased osteoblasts
What occurs in pagets disease?
imbalance of osteoblast and osteoclast function
-abnormal mosaic bone architecture
What are the stages of pagets disease?
- lytic -osteoclastic
- mixed - osteoclastic and osteoblastic
- sclerotic - osteoblasts
- burnt out phase - little cell activity
What is abnormal in the labs in pagets disease?
increased ALP
