A.15 bone mineral homeostasis

Question 1

what are the primary hormonal modulators of bone mineral homeostasis?

Answer 1

parathyroid hormone (PTH)
Vitamin D

Question 2

what are the secondary hormonal modulators of bone mineral homeostasis?

Answer 2

calcitonin, estrogens, glucocorticoids

Question 3

what are the non-hormonal modulators of bone mineral homeostasis?

Answer 3

Bisphosphonates
RANK-ligand inhibitors
Calcimimetics
Fluoride

Question 4

what is Teriparatide and how is it given?

Answer 4

PTH analogue, SC injection

Question 5

what is the indication for teriparatide?

Answer 5

osteoporosis

Question 6

SE of teriparatide?

Answer 6

hypercalcemia, hypercalcuria

Question 7

function of PTH

Answer 7

1. kidney: Ca² excretion↓ P excretion ↑, synthesis of vit D
2. bone: osteoclast and osteoblast stimulation
3. intestine: Ca² and P absorption ↑ (indirect effect mediated by vit D)

net effect: Ca² ↑ P ↓

Question 8

function of Vitamin D

Answer 8

1. kidney: Ca² and P reabsorption↑
2. bone: direct effect–> bone resorption ↑serum Ca² and P
3. intestine: Ca² and P absorption↑
4. inhibit PTH release

net effect: Ca² ↑ P ↑

Question 9

what do vitamin d2 and d3 require that calcitriol (active form) doesn’t?

Answer 9

metabolism in liver or kidney to become active

Question 10

analogue of calcitriol

Answer 10

doxercalciferol
paricalcitol
calcipotriene

Question 11

which vitamin D drug is given topically?

Answer 11

calcipotriene

Question 12

indications for Ergocalciferol (Vit D2) and Cholecalciferol (Vit D3) ?

Answer 12

vitamin D deficiency- rickets disease, osteomalacia, nutritional deficiency, hypoparathyroidism, nephrotic syndrome

Question 13

SE of Ergocalciferol (Vit D2) and Cholecalciferol (Vit D3)

Answer 13

hypercalcemia, hyperphosphatemia, hypercalcuria

Question 14

indications for calcitriol

Answer 14

secondary hyperparathyroidism in patients with chronic kidney disease
hypocalcemia in patients with hypoparathyroidism

Question 15

indications for Doxercalciferol and paricalcitol?

Answer 15

secondary hyperparathyroidism in patients with chronic kidney disease
(milder SE than calcitriol)

Question 16

indication for calcipotriene

Answer 16

psoriasis

Question 17

function of calcitonin

Answer 17

1. Kidney: Ca² and P excretion↑
2. inhibits osteoclast activity–>↓ bone resorption

net effect: Ca²↓
CALCITONIN –>tones down the Ca² level, keeps it in the bones.

Question 18

how is calcitonin given?

Answer 18

SC, nasal spray

Question 19

indications for calcitonin

Answer 19

osteoporosis
paget’s disease
hypercalcemia- acute management

Question 20

SE of calcitonin

Answer 20

rhinitis with the nasal spray, hypocalcemia

Question 21

What is Raloxifene and what is it’s function

Answer 21

SERM- selective estrogen receptor modulator

inhibits PTH-induced bone resorption by inhibiting osteoclast activity

Question 22

indication for raloxifene

Answer 22

post-menopausal osteoprosis

Question 23

SE of Raloxifene

Answer 23

hot flushes, ↑ risk of venous thromboembolism

Question 24

glucocorticoids function

Answer 24

1. intestinal and renal Ca² absorption↓
2. RANK-L stimulation
3. inhibit osteoblast and collagen synthesis

Question 25

what risk is there in prolonged use of GC?

Answer 25

osteoporosis (in systemic therapy)

Question 26

name 2 bisphosphonates

Answer 26

Alendronate
Zoledronate
Risedronate

Question 27

what is the function of bisphosphonates?

Answer 27

1. direct suppression of osteoclast activity

2. increase of bone mineral density in the first year of use

Question 28

how is alendronate given?

Answer 28

oral or parenteral

Question 29

indications for alendronate, zoledronate?

Answer 29

osteoporosis (1st line treatment)
Paget’s disease
bone metastasis
hypercalcemia due to hyperparathyroidism

Question 30

SE for bisphosphonates?

Answer 30

hypocalcemia, upper GI irritation, osteonecrosis of the jaw (rare, with IV use)

Question 31

what is Denosumab and how is it given?

Answer 31

RANK-ligand inhibitor
human monoclonal antibody (IgG)
SC injection every 6 months

Question 32

what is the function of denosumab?

Answer 32

inhibit RANK-L stimulation of osteoclast activity–> ↓ bone resorption

Question 33

indication of denosumab?

Answer 33

Post-menopausal osteoporosis

Question 34

SE of denosumab

Answer 34

increased risk of infection

Question 35

what is Cinacalcet and how is it given?

Answer 35

it’s a calcimimetic (mimics the action of Ca² on tissues)
activates Ca² sensing receptor–> ↓PTH–> ↓ Ca²
given orally

Question 36

indications for Cinacalcet

Answer 36

secondary hyperparathyroidism due to chronic kidney disease

parathyroid carcinoma management

Question 37

SE of Cinacalcet

Answer 37

nausea, hypocalcemia

Question 38

risk factors for developing primary osteoporosis

Answer 38

endocrine: hypothyroidism, Type 1 DM
GI: malabsorption, vitamin D and C deficiency
Drug-induced: anticoagulants, chemotherapy , alcohol

Question 39

what is osteoporosis?

Answer 39

reduction of the bone strength that leads to an increased risk of fractures (vertebal and hip mostly)

Question 40

how do we measure bone mineral density?

Answer 40

DEXA scan - dual energy X-ray absorptiometry

graded based on the T score

Question 41

classification of BMD (based on T score)

Answer 41

normal: -1.0 or greater
osteopenia: between -1.0 and -2.5
osteoporosis: -2.5 or less
severe osteoporosis: -2.5 or less with a pathologic fracture

Question 42

pharmacological management of osteoporosis

Answer 42

1. SERM- Raloxifene
2. Bisphosphonate
3. RANK-L inhibitors (denosumab)
4. calcitonin analogues
5. PTH analogues
6. Ca² supplementation
7. Vitamin D supplementation
8. thiazide diuretics