Bone Disorders

Question 1

Outline what occurs in bone remodelling

Answer 1

Osteoclasts absorb old bone before being replaced by osteoblasts which lay down osteoid that is mineralised to new bone

Question 2

What is bone mineral density a measure of?

Answer 2

Fracture risk independent of other factors

Question 3

What scan is used to measure bone density?

Answer 3

DEXA

Question 4

What is defined as a normal bone mineral density?

Answer 4

Bone density within one standard deviation of the young adult reference mean

Question 5

What is defined as osteopenic bone mineral density?

Answer 5

Bone mineral density that is between 1 and 2.5 standard deviations below the mean

Question 6

What is defined as osteoporotic bone density?

Answer 6

Bone mineral density more than 2.5 standard deviations below the young adult mean

Question 7

What bloods should be measured in suspected osteoporosis?

Answer 7

U+Es
LFTs
PV
FBC
TSH

Question 8

Give some secondary causes of osteoporosis

Answer 8

Hyperthyroidism
Cushing’s
Coeliac

Question 9

What drug treatments are used in osteoporosis?

Answer 9

Calcium and Vit D supplements
Bisphosphonates
Denosumab
Teriparatide

Question 10

Give some examples of bisphosphonates

Answer 10

Alendronate

Risedronate

Question 11

How do bisphosphonates work?

Answer 11

Reduce osteoclast cell number and activity

Question 12

How and how often is zoledronic acid given?

Answer 12

Once yearly

IV infusion

Question 13

How does denosumab work?

Answer 13

Binds to RANK-L preventing activation of RANK thus inhibiting development/activity of osteoclasts

Question 14

Denosumab can be used in renal impairment. True/false?

Answer 14

True

Question 15

How does teriparatide work?

Answer 15

Parathyroid hormone that stimulates bone growth

Question 16

Give some effects of steroids on bone

Answer 16

Reduce osteoblast activity

Suppress osteoblast precursor replication

Question 17

Patients taking steroids for more than 3 months should be considered for calcium supplementation. True/false?

Answer 17

False - 2 months

Question 18

What is Paget’s disease?

Answer 18

Abnormal osteoclastic activity followed by increased osteoblastic activity

Question 19

Which bones are commonly affected by Paget’s?

Answer 19

Long bones
Pelvis
Lumbar spine
Skull

Question 20

What LFT may be raised in Paget’s?

Answer 20

ALP

Question 21

What causes osteogenesis imperfecta?

Answer 21

Mutations of type I collagen genes

Question 22

What eye feature is osteogenesis imperfecta associated with?

Answer 22

Blue sclerae