Osteoporosis

Question 1

Define osteoporosis

Answer 1

Reduced bone density (defined as >2.5 standard deviations below peak bone mass achieved by healthy adults - T-score >2.5) resulting in bone fragility & increased fracture risk

Question 2

Aetiology of primary osteoporosis

2

Answer 2

Idiopathic (if <50 yrs)

Post menopausal

Question 3

Aetiology of secondary osteoporosis

5 w/ examples

Answer 3

Malignancy
myeloma
metastatic carcinoma

Endocrine
Cushing’s disease
thyrotoxicosis
primary hyperparathyroidism
hypogonadism 

Drugs
corticosteroids
heparin

Rheumatological
rheumatoid arthritis
ankylosing spondylitis

Gastrointestinal
malabsorption (e.g. coeliac disease, partial gastrectomy)
liver disease (e.g. primary biliary cirrhosis)
anorexia

Question 4

Risk factors for osteoporosis

11

Answer 4

Age
FH
Low BMI
Low calcium intake
Smoking
Lack of physical exercise
Low exposure to sunlight
Alcohol abuse
Late menarche
Early menopause
Hypogonadism

Question 5

Epidemiology of osteoporosis

prevalence, genders, ethnicity

Answer 5

COMMON
In >50 yrs old: 1/3 females & 1/12 males
More common in CAUCASIANS than Afro Caribbeans

Question 6

Presenting symptoms of osteoporosis

general +3

Answer 6

Often asymptomatic until fractured occur

Characteristic fractures:
neck of femur (after minimal trauma)
vertebral fractures (leading to loss of hight, stooped prostate & cute back pain on lifting)
Colles’ fracture (of distal radius after falling on outstretched hand)

Question 7

Signs of osteoporosis on physical examination

general +3

Answer 7

Often no signs until complications develop:
Tenderness on percussion (over vertebral fractures)
Thoracic kyphosis (due to multiple vertebral fractures)
Severe pain when hip flexed & externally rotates (suggests NOF fracture)

Question 8

Investigations for osteoporosis

4 groups

Answer 8

Bloods
Xray
Isotope bone scans
DEXA scan

Question 9

Investigations for osteoporosis - bloods

3

Answer 9

Calcium
Phosphate
ALP
NORMAL in primary osteoporosis

Question 10

Investigations for osteoporosis - X-ray

3

Answer 10

Used to diagnose fractures
Often normal because it takes >30% loss of bone density before showing any changes in radiolucency or cortical thinning
May show biconcave vertebrae & crush fractures

Question 11

Investigations for osteoporosis - isotope bone scans

Answer 11

Highlights areas of stress & microfractures

Question 12

Investigations for osteoporosis - DEXA scan

2

Answer 12

T-score = number of s.d. BMD measurement is above or below the young normal mean BMD 
Z-score = number of s.d. measurement is above or below the age matched mean BMD - may be helpful in identifying patient that need work up for secondary causes of osteoporosis