Biochemical Disorders of Bone

Question 1

What characterizes osteoporosis?

Answer 1

reduced bone mineral density

increased porosity

Question 2

What is bone mineral density of osteoporosis defined as in terms of standard deviations below the mean?

Answer 2

less than 2.5 standard deviations below the mean

Question 3

What is bone mineral density of osteopenia defined as in terms of standard deviations below the mean?

Answer 3

between 1-2.5 standard deviations below the mean

Question 4

When does loss of bone mineral density tend to occur?

Answer 4

30 yrs

Question 5

Why do women tend to lose more bone mineral density after the menopause?

Answer 5

increase in osteoclastic bone resorption due to loss of protective effects of oestrogen

Question 6

What are the two types of primary osteoporosis?

Answer 6

Type 1 = post menopausal

Type 2 = osteoporosis of old age

Question 7

What are the added risk factors in type 2 osteoporosis?

Answer 7

sunlight exposure reduced, chronic disease, inactivity

Question 8

What type of fractures tend to occur in type 1 osteoporosis?

Answer 8

colles fractures

vertebral insufficiency fractures

Question 9

What type of fractures tend to occur in type 2 osteoporosis?

Answer 9

femoral neck fractures

vertebral fractures

Question 10

What can osteoporosis occur secondary to?

Answer 10

alcohol abuse, steroid use, malnutrition, chronic disease eg CKD, malignancy, RA and endocrine disorders (Cushings, hyperthyroid, hyperparathyroid)

Question 11

How is osteoporosis diagnosed?

Answer 11

DEXA scanning

Question 12

What happens to serum calcium and phosphate in osteoporosis?

Answer 12

are normal

Question 13

Can any treatment s increase BMD?

Answer 13

no

Question 14

What is the mainstay of treatment in osteoporosis?

Answer 14

slow any further deterioration/decrease fracture risk

Question 15

How can peak bone mineral density be built up?

Answer 15

exercise, healthy lifestyle

Question 16

What treatments are used to try to prevent fractures?

Answer 16

calcium and vit D supplements, bisphosphonates, Desunomab and strontium

Question 17

What do bisphosphonates do?

Answer 17

reduce osteoclastic resorption

Question 18

What are examples of bisphosphonates?

Answer 18

end in ate eg alendronate

Question 19

What does strontium do?

Answer 19

increases osteoblast replication and reduces resorption

Question 20

Is HRT a first line agent for prevention of osteoporosis after menopause?

Answer 20

No but can be considered if side effects with other medications occur

Question 21

What are risks of HRT?

Answer 21

increast breast cancer/endometrial cancer rates

DVT

Question 22

Does raloxifene (oestrogen receptor modulator) have a risk of DVT?

Answer 22

yes

Question 23

What currently have the greatest evidence for efficacy, cost effectiveness and low side effect profile in terms of osteoporosis treatment?

Answer 23

bisphosphonates

Question 24

What is osteomalacia?

Answer 24

qualitative defect of bone with abnormal softening of bone

Question 25

What are there inadequate amounts of in osteomalacia?

Answer 25

calcium and phosphorus

Question 26

What is the same as osteomalacia?

Answer 26

rickets

Question 27

What may cause hypophosphataemia (a cause of osteomalacia)?

Answer 27

re feeding syndrome, alcohol abuse, malabsorption, renal tubular acidosis

Question 28

What may patients complain of in osteomalacia?

Answer 28

bone pain, deformities

Question 29

What may radiographs show in osteomalacia?

Answer 29

pseudofractures aka Looser’s zones

Question 30

What is serum bone biochemistry like in osteomalacia?

Answer 30

low calcium, low phosphate, high ALP

Question 31

Treatment of osteomalacia?

Answer 31

vit D therapy with calcium and phosphate supplements

Question 32

What is primary hyperparathyroidism due to?

Answer 32

benign adenoma, hyperplasia or perhaps malignant neoplasia

Question 33

What does overproduction of PTH lead to?

Answer 33

hypercalcaemia

Question 34

Symptoms and signs of hypercalcaemia?

Answer 34

fatigue, nausea, depression, polyuria, renal stones, osteoporosis etc etc

Question 35

In hyperparathyroidism what happens to phosphate?

Answer 35

is normal or low

Question 36

What is secondary hyperparathyroidism?

Answer 36

overproduction of PTH secondary to hypocalcaemia caused by vitamin D deficiency OR CKD

Question 37

What is tertiary hyperparathyroidism?

Answer 37

patients with secondary hyperparathyroidism who develop an adenoma which will continue to produce PTH, usually CKD related