Metabolic Bone Disease

Question 1

Hx questions for metabolic bone disease

Answer 1

Risk factors:

• Exercise levels
• Smoker
• Co-morbidities (RA, T2DM)
• Nutrition, calcium intake
• Vitamin D exposure
• Prolonged amenorrhoea (when was your last period)
• Post menopausal age
• Malabsorption (coeliac, IBD)

Other:
- FHx

• Fracture history
• Pathological fracture: Any fracture from a fall from a standing height? * minimal trauma fracture: wrist, hip, spine
• Previous or current therapies for postmenopausal osteoporosis
• Rx: corticosteroids

Question 2

Ix for osteoporosis

Answer 2

Pathology:

• FBE, U&Es, LFTs
• Pentad: Serum Ca and PO4, Vitamin D, PTH, Renal Function
• Thyroid (hyperthyroidism), cortisol,
• Myeloma screen: bone marrow aspirate, electrophoresis for free light chain in urine and serum (Bence Jones protein test in urine)
• Inflammatory marker: ESR, CRP
• Bone turnover markers: resporption serum b-CTX; formation P1NP (bone formation marker)

Radiology:

• Xray: lateral spine
• DEXA (

Question 3

If you order serum Ca and PO4, what else needs to be ordered?

Answer 3

Pentad of tests that must be ordered to interpret one of them:
Serum Ca, PO4, Vitamin D, PTH, Renal Function

Question 4

DEXA scan score components

Answer 4

T score: compared with normal peak bone mass person of same sex and ethnicity

Z score (in relation to ppl similar to you): compared with age, gender, ethinicity

Question 5

Osteoporotic T score

Question 6

Osteopaenic T score

Question 7

Normal T score

Answer 7

> -1

Question 8

For every 1 SD from normal, the relative risk of fracture increased by ___

Answer 8

1.5- to 2.5- fold

Question 9

Sources of ALP

Answer 9

BLIP:
Bone 
Liver
instestine
Placenta

Question 10

What risk assessment tool is used to asses the absolute fracture risk?

Answer 10

FRAX- WHO:

WHO fracture risk assessment (Garvan Tool)

Question 11

Rx of osteoporosis

Answer 11

a. HRT
b. Raloxifene (women only): SERM
c. Bisphosphonates - (Alendronate, Risedronate, Zolendronate)
e. Teriparatide
f. Denosumab

Question 12

AFx of bisphosphonate

Answer 12

1. GORD (make worse or new onset)
2. osteonecrosis of jaw post dentition work when pulling out teeth. It leads to raw/open jaw bone and cannot heal with osteoclast inhibition
3. eGFR

Question 13

MoA of HRT

Answer 13

Normally osteoblasts produce RANKL binds to RANK receptor on osteoclasts leading to formation activity and survival stimulation

HRT and SERMs osteoblasts from releasing RANKL molecule

Question 14

MoA of bisphosphonates

Answer 14

inhibit osteoclast action and increase osteoclast apoptosis

Question 15

MoA of denosumab

Answer 15

RANKL inhibitor

Question 16

MoA of teriparatide

Answer 16

intermittent PTH stimulates osteoblasts