Bone pt 2

Question 1

What are causes of rickets/osteomalacia?

Answer 1

1. low vit D
2. phosphate deficiency
   both cause defects in mineralization

Question 2

What is x linked hypoP?

Answer 2

most common type of hereditary rickets

FGF23 cant be inactivated - renal P wasting

Question 3

What is wasted renally in fanconi syndrome?

Answer 3

P, glucose, bicarb, amino acids

Question 4

If a tumor is causing osteomalacia, what is it secreting? what is the action of this hormone?

Answer 4

paraneoplastic phosphatonins

-inhibit inactivation of FGF23 - renal P wasting

Question 5

How would you determine rickets vs osteomalacia?

Answer 5

rickets occurs when the growth plate is still open

Question 6

What is the pathognomonic shape of the epiphysis in rickets?

Answer 6

flared and cup shaped

Question 7

What are some physical signs of rickets?

Answer 7

1. pigeon breast deformity
2. frontal bossing - prominent forehead
3. rachitic rosary - osteoid deposition on chondrocostal junction
4. bowing of the legs

Question 8

What are the lab findings in osteomalacia /rickets?

Answer 8

1. dec serum calcium
2. dec serum phosphate
3. inc PTH
4. inc alkaline phosphatase - inc osteoblast activity
   - need alkaline envt to add calcium

Question 9

What occurs in osteoporosis?

Answer 9

loss of trabecular bone mass - porous bone at risk for fracture

Question 10

What are the lab values in osteoporosis?

Answer 10

serum values are normal but DEXA scan shows decreased bone density

Question 11

When does your bone density peak?

Answer 11

age 30

Question 12

What are two types of osteoporosis?

Answer 12

1. estrogen deficient - women
   - increased osteoclasts
2. senile - men and women >70
   - decreased osteoblasts

Question 13

What occurs in pagets disease?

Answer 13

imbalance of osteoblast and osteoclast function

-abnormal mosaic bone architecture

Question 14

What are the stages of pagets disease?

Answer 14

1. lytic -osteoclastic
2. mixed - osteoclastic and osteoblastic
3. sclerotic - osteoblasts
4. burnt out phase - little cell activity

Question 15

What is abnormal in the labs in pagets disease?

Answer 15

increased ALP

Question 16

What are some physical signs of pagets disease?

Answer 16

1. increased hat size - typically affects facial bones
2. hearing loss - impingement of CNs
3. lion like faces
4. lightheadness - pagetic steal

Question 17

What are some unfortunate complications of pagets disease?

Answer 17

1. high output failure

2. osteosarcoma