Metabolic bone disease

Question 1

How do we describe calcium that is bound to albumin?

Answer 1

Inactive

Question 2

How much calcium in urine per day?

Answer 2

0.2g/day (same amount that is gained in the intestine)

Question 3

what fraction of the ca we eat gets absorbed?

Answer 3

1/5

Question 4

What percentage of Ca is reabsorbed from the glomerular filtrate?

Answer 4

98%

Question 5

What mass of calcium per day is engaged in bone turnover?

Answer 5

0.5g (more in growing person or if preggas)

Question 6

Where do we get Vitamin D3 from?

Answer 6

Fish, meat

Question 7

Where vit D2 from?

Answer 7

Vitamin supplements

Question 8

why is sunlight needed in vitamin D metabolism>

Answer 8

Needed to convert 7-dehydrocholesterol into vitamin d3

Question 9

Which hormone maintains calcium balance in the body?

Answer 9

PTH (parathyroid hormone) - low serum calcium means PTH secretion increased.

Question 10

How many parathyroid glands is there?

Answer 10

4

Question 11

What does PTH do?

Answer 11

Stimulates the enzyme that activates vitamin D, which increases calcitriol production from kidney and decreases calcium excretion.

Question 12

Radioisotope scanning - what can this highlight?

Answer 12

Fracture, bone infection, cancerous deposit

Question 13

What does dual energy X ray absorpitometry assess? (DEXA)

Answer 13

Bone mineral density - can be used to diagnose osteoporosis.

Question 14

What is PRIMARY hyperparathyroidism?

Answer 14

Excessive PTH secretion resulting in hypercalcaemia.

Question 15

What is SECONDARY parathyroidism?

Answer 15

PTH above normal level but APPROPRIATE (calcium is low), PTH should be higher to raise the low level of calcium.

Question 16

4 reasons why someone may be vitamin D deficient?

Answer 16

Lack of sunlight, dietary lack, malabsorption, impaired activation - renal failure.

Question 17

3 causes of rickets?

Answer 17

Phosphaturia and low Ca intake

Question 18

what is tetany?

Answer 18

muscle spasms due to low calcium in bones

Question 19

2 activated forms of vitamin D you can give?

Answer 19

Alfacalcidol or calcitriol (given in kidney disease)

Question 20

Effects of Pagets disease?

Answer 20

Deafness, uncoordinated bone remodelling, pain, nerve compression, bones more likely to fracture

Question 21

Treatment of pagets?

Answer 21

bisphosphonates, - they inhibit osteoclasts (all end in ate)

Question 22

T score in osteoporosis?

Answer 22

-2.5 or lower

Question 23

Treatment of osteoporosis?

Answer 23

Low dose bisphosphonates, HRT, Ca and D3, Denosumab, PTH injections

Question 24

what can a high dose of bisphosphonates cause?

Answer 24

Bisphosphonate related osteonecrosis of the jaw

Question 25

common sites of bone mestastases

Answer 25

great lung and prostate

Question 26

Myeloma?

Answer 26

malignancy of plasma cells in bone marrow

Question 27

what is vitamin D3 stored as in the liver

Answer 27

25-vitd3

Question 28

what is alkaline phosphatase associated with?

Answer 28

osteoblasts

Question 29

when are Beta crosslaps levels used

Answer 29

post menopausal women

Question 30

difference between pagets and osteoporosis

Answer 30

pagets is more localised

Question 31

osteonecrosis of the jaw key drug

Answer 31

denosumab