Osteoporosis

Question 1

Define osteoporosis.

Answer 1

Skeletal disorder characterised by COMPROMISED BONE STRENGTH leading to INCREASED RISK OF FRACTURE caused by DECREASED BONE DENSITY/QUALITY

Question 2

List 3 causes of osteoporosis.

Answer 2

Menopause
Hyperparathyroidism
Low dietary calcium

Question 3

List 3 fractures which are especially common in osteoporosis.

Answer 3

Colles’ wrist fracture
Vertebral compression fracture
Femoral neck fracture

Question 4

List 8 risk factors for osteoporotic fractures.

Answer 4

Age 65+
Decreased bone mineral density
Previous fracture
Family history
Early menopause
Primary hyperparathyroidism
Long term steroids
Propensity to fall

Question 5

List 6 complications of osteoporotic fractures.

Answer 5

Disability
Death
Kyphosis
Loss of height
Crowding of organs
Back pain

Question 6

Which investigations would you do for osteoporosis? (2)

Answer 6

DEXA scans

FRAX fracture risk calculation

Question 7

What calculation is done by the DEXA scan to assess bone mineral density?

Define it.

Answer 7

t-score

Def.: “Number of standard deviations above or below the mean for a healthy adult population of the same sex and ethnicity as the patient”

Question 8

How do you interpret the t-score results of a DEXA scan? (4)

Answer 8

Normal: -1.0+
Osteopenia: -1 to -2.5
Osteoporosis: -2.5+

Established osteoporosis: -2.5+ PLUS previous fracture

Question 9

What are the main variables which a FRAX calculation takes into account to measure fracture risk? (3)

Answer 9

Age
Bone mineral density
Previous fractures

Question 10

What are the 3 main aspects of managing osteoporosis?

Answer 10

Decrease risk of falls
Lifestyle changes
Pharmacological treatment

Question 11

How would you decrease the risk of falls in osteoporosis? (4)

Answer 11

Avoid drugs with sedative effects
Treat sensory deficits (e.g. impaired vision)
Gait and balance training
Occupational therapy

Question 12

Which lifestyle changes would you recommend in osteoporosis? (4)

Answer 12

Adequate dietary calcium
Regular exercise
Smoking cessation
Avoid alcohol

Question 13

What is the main pharmacological treatment for osteoporosis?

List 5 other drugs which can be used.

Answer 13

Bisphosphonates

OTHER DRUGS:
Calcium/vitamin D
Hormone replacement therapy
Selective oestrogen receptor modulator (SERM)
Teriparatide
Denosumab

Question 14

Give 2 examples of bisphosphonates.

Describe their mechanism of action. (2)

Answer 14

Alendronic acid (alendronate)
Ibandronate

MECHANISM OF ACTION:

1. Inhibit osteoclast bone resorption
2. No effect on osteoblasts

Question 15

List 5 side effects of bisphosphonates.

Answer 15

Dyspepsia
Dysphagia
Abdominal pain
Headache
Acid regurgitation

Question 16

Give 1 example of a selective oestrogen receptor modulator (SERM).

Answer 16

Raloxifene

Question 17

Describe the mechanism of action of teriparatide. (1)

Answer 17

1. PTH analogue

Question 18

Describe the mechanism of action of denosumab. (1)

Answer 18

1. Monoclonal antibody against RANKL

a. Therefore prevents osteoclast activation

Question 19

Describe the RANK-RANKL system in bone remodelling. (3)

Answer 19

1. Pre-osteoclasts express RANK on their surface
2. When stimulated, pre-osteoblasts secrete RANKL
3. RANKL binds to RANK and activates pre-osteoclasts to form active osteoclasts

Question 20

Describe the role of osteoprotegerin in bone remodelling. (3)

Answer 20

1. Secreted by mature osteoblasts
2. Binds to RANKL (secreted by pre-osteoblasts)
3. Therefore RANKL can no longer bind to RANK on pre-osteoclasts
   a. Therefore there is no osteoclast activation