Osteoporosis

Question 1

What is osteoporosis?

Answer 1

Weak bones due to decreased bone mass.

Question 2

Give the main cause of primary osteoporosis and 2 others.

Answer 2

Mainly increasing age
Parental history
Alcohol >4 units daily
RA 
BMI <19
Sedentary lifestyle/ immobility
Menopause

Question 3

Give 3 causes of secondary osteoporosis.

Answer 3

SHATTERED
Steroid use
Hyper-: thyroidism, parathyroidism, calciuria
Alcohol and smoking
Thin 
low Testosterone 
Early menopause
Renal or liver failure
Erosive/inflammatory bone disease (RA)
Diet - hypocalcaemia, DM type 1.
(OHCM)

Question 4

Describe the epidemiology of osteoporosis.

Answer 4

Female (due to loss of trabeculae)

Over 50

Question 5

What is the pathophysiology of OP?

Answer 5

Imbalance between bone resorption and formation, due to inadequate peak bone mass, excessive bone resorption and/or inadequate formation of new bone during remodelling.

Question 6

How does osteoporosis usually present?

Answer 6

Can be asymptomatic until fracture occurs.

Trabecular bone affects -> crush fractures of vertebrae cause hunched spine.

Question 7

Which types of fractures are more likely if cortical bone is affected?

Answer 7

Long bone fractures such as neck of femur.

Question 8

What is the main investigation needed if someone has a low-trauma fracture?

Answer 8

DEXA scan of hip - compares bone mineral density with that of a young healthy adult, giving a ‘T-score’, which is the number of standard deviations between the scores.

Question 9

What does a T score of -2.5 < -1 mean?

Answer 9

Osteopenia - risk of later osteoporotic fracture (offer lifestyle advice).

Question 10

What does a T score of

Answer 10

Osteoporosis.

Question 11

Give 3 lifestyle measures to decrease risk of OP fractures.

Answer 11

Decrease OP:
Quit smoking
Reduce alcohol consumption
Weight-bearing exercise
Increase Ca and vit D intake
Reduce risk of falls:
Balance exercise eg tai chi 
Home-based fall prevention programme.

Question 12

Describe the pharmacological management of OP.

Answer 12

1. Bisphosphonates - alendronic acid
2. Calcium and vitamin D
3. Hormone replacement therapy/ selective estrogen receptor modulator eg raloxifene.

Question 13

Alendronic acid - mechanism, side-effects?

Answer 13

Inhibits osteoclast-mediated bone resorption. SE: photosensitivity, GI upset, oesophageal ulcers.

Question 14

What is the systemic bioavailability of alendronic acid and what can optimise it?

Answer 14

0.6% (low). Decreased further by intake with meals or beverages, so wait 30 mins before eating/drugs.