Osteoporosis

Question 1

Definition of osteoporosis according to bone mass density

Answer 1

Based on the mean bone mineral density of a healthy 30 year old Caucasian female

• Normal - BMD within 1 SD of mean
• Osteopenia - BMD 1-2.5 SD of mean
• Osteoporosis - BMD 2.5 SD below mean
• Severe/established osteoporosis - BMD 2.5 SD below mean plus an osteoporotic fracture

Question 2

Non-modifiable risk factors for osteoporosis (5)

Answer 2

• Age over 50 (women) or 65 (men)
• Post-menopause or early menopause
• Caucasian
• Family history
• Past pathological fracture

Question 3

Modifiable risk factors for osteoporosis (6)

Answer 3

• Malnutrition
  
  • Vitamin D/calcium deficiency
• Sedentary lifestyle, immobilisation, space flight
• Low BMI
• Smoking
• Alcohol
• Heavy metals (cadmium and lead)

Question 4

Medical disorders related to osteoporosis (8)

Answer 4

• Osteogenesis imperfecta
  
  • Rare defect in collagen synthesis
  • Classic sign - blue sclera
• Rheumatological
  
  • RA, ankylosing spondylitis, SLE, amyloidosis, sarcoidosis
• Hypogonadism
  
  • Turner’s, Klinefelter’s, Kallman, anorexia nervosa, hypothalamic amenorrhoea, andopause
• Endocrine
  
  • Hyperparathyroidism, Cushings, DM, acromegaly, pregnancy and lactation, thyrotoxicosis
• Malabsorption
  
  • Coeliac, Crohn’s, UC, CF, lactose intolerance, short bowel syndrome, bulimia
• Renal insufficiency
  
  • Renal osteodystrophy
• Haematologic
  
  • Multiple myeloma, malignancies
• Parkinson’s
  
  • Falls + decreased BMD

Question 5

Drugs causing osteoporosis (9)

AT PLASMA

Answer 5

• Anticoagulants (heparin and warfarin)
• TZDs (glitazones)
• PPIs
• Lithium
• Aromatase inhibitors
• Steroids
• Methotrexate
• Antiepileptics (accelerate vitamin D metabolism)

Question 6

Areas most commonly affected by osteoporosis, and why

Answer 6

Wrist, hip and spine - due to high trabecular bone to cortical bone ratio

Question 7

Bloods you may order in osteoporosis (9)

Answer 7

• Serum calcium
• Urinary free cortisol
• Serum phosphate
• Serum vitamin D
• Serum PTH
• TFTs
• Serum testosterone
• LFTs
• UECs

Question 8

Biochemical markers of osteoporosis (3)

Answer 8

• Serum procollagen type IN propeptide (PINP)
• Cathepsin K
• C-telopeptides

Question 9

DEXA scan

• Location of measurement
• Two type of results yielded
• What can falsely increase the reading?

Answer 9

• Measured at hip and lumbar
• T score and Z score
  
  • T score = number of SDs from that of a healthy young adult
  • Z score = number of SDs from that of a patient of the same age, sex and ethnicity
• Osteophytes can falsely increase BMD

Question 10

• Falls prevention
• Diet/supplements (Ca, vit D)
• Weight-bearing exercise

Question 11

Pharmacological management of osteoporosis (6)

• Mechanism of action
• Adverse effects

Answer 11