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Flashcards in OSTEOPOROSIS Deck (45)
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1
Q

For every 1SD below normal T score (T score below -1), , relative risk of fracture is increased by…

A

1.5-1.5 fold

2
Q

Normal BMD

A

Over T score -1

3
Q

osteopenia definition

A

-1 to -2.5 T score

4
Q

osteoporosis

A

less than -2.5 T score

5
Q

Severe osteoporosis

A

below -2.5 T score and at least one fracture

6
Q

When to use Z score

A

when below -2 may be useful in identifying those with accelerated cause of bone loss

7
Q

When to use FRAX and when to use Garvan institute

A

Frax is a tool only valid in over 40s. Garvan better if older as includes recent falls in data. Recommend treatment if 10 year risk of hip fracture over 3 percent and 10 year risk of any fracture over 14%- but PBS reimbursement not based on this yet

8
Q

Physically, what is the glucocorticoid effect on bones

A

Loss of both horizontal and vertical trabeculae there for tend to fracture at relatively higher BMD. Glucocort and below -1.5 get bisphos on PBS

9
Q

What is the evidence for calcium and vitamin D in reducing fractures

A

RECORD trial- no effect- but poor compliance in this trial
Associated with- reduced bone loss at hip and spine
In trials with greater compliance, reduction in any fracture, osteoporotic fracture (33%)
Need higher doses in fat people as fat soluble
Most benefit is for people with lower baseline vitamin D

10
Q

Effects of calcium on MI

A

insufficient evidence to support this finding- analysed trials were not designed to assess impact of calcium on CV risk. Data conflicting.
Numerous large studies- no increase in CV event risk
Food best source calcium, supplement only if cannot be achieved
Elderly and others with impaired renal function who take supplements may be at higher risk of CVD
Lower doses calcium (500-600mg) likely to be as effective

11
Q

Side effects of raloxifene

A

Hot flushes, leg cramps. Only spinal fracture risk reduction

12
Q

Should you delay administration of a bisphosphonate in the acute post fracture period?

A

Better to delay ZA administration 2 weeks post fracture

No evidence of impaired healing, actually strengthen callus formation

13
Q

Is strontium ranelate associated with ONJ?

A

No

14
Q

What can happen when you take bisphosphonates for more than 7 years?

A
Femural stress fractures
Ask for thigh or groin pain
Plain films may show periostial elevation - bone scan sees hot spots. 
Stop treatments. 
1 in 1000 to 10000 on treatment
15
Q

Criteria for teriparatide on PBS?

A

T score below -3 and 2 minimal trauma fractures and intolerant to bisphosphonates or one fracture has happened after at least 12 months on a bisphosphonate

16
Q

Black box warning on teriparatide why?

A

In a rat strain prone to cancer long term teriparatide caused osteogenic sarcoma
2 cases in half a million people

17
Q

Strontium ranelate effect on MI?

A

Increase risk of MI but not mortality - in postmenopausal women over age 75

18
Q

Rate of ONJ in malignancy and osteoporosis

A

malig: 0.8-12%
osteoporosis: 1 in 1000 to 1 in 10000

** new name is antiresorptive associated ONJ, as denosumab also does this

19
Q

RISK FACTORS for ONJ

A
malignancy
smoking
age over 65
use of bisphosphonates more than 2 years
denture wearing
diabetes
invasive procedures like tooth extractions
periodontitis
20
Q

What are the best markers of new bone formation?

A

bone specific ALP
P1NP

(also osteocalcin)

21
Q

What are the best markers of bone destruction?

A

C-telopeptide cross links (serum)

N-telopeptide cross links (uriNe)

22
Q

How do you best characterise bone loss in men vs women with age?

A

At menopause there is an ACCELERATED PHASE OF TRABECULAR BONE LOSS which is from trabecular perforation and loss of connectivity.

This is followed by a slower phase that occurs in both med and women - affects CORTICAL SITES. Reduced osteoblast numbers, number of trabeculae. DECREASED WALL WIDTH is the most consistent finding in men and women with osteoporosis who are older.

Bone loss in older men is associated with trabecular thinning rather than perforation.

Oestrogen deficiency leads to cortical bone loss.

23
Q

Explain the system with RANK, RANKL, OPG, and denosumab.

A

Normally, RANKL on osteoblasts binds to RANK on pre-osteoclasts, which triggers maturation and bone resorption. Osteoblasts secrete OPG, which binds to their own RANKL to prevent this from happening.

Denosumab is a monoclonal against RANKL, mimicking the OPG effect.

24
Q

Mechanism of action of bisphosphonates

A

Inhibit enzyme farnesyl pyrophosphate synthase in osteoCLASTS which is involved in cholesterol synthesis . Intermediate metabolites of the pathway are needed for cell membrane ruffled border. Loss ruffled border means cannot absorb so eventually apoptose.

25
Q

What is the relationship between ZA and AF?

A

May precipitate AF

26
Q

What are the PBS guidelines for malignancy?

A

CS more thatn 3 months and T score under -1.5
Over 70 and BMD under -2.5
Fragility fracture
Pagets disease
MM, castration resistant prostate ca, breast ca with bony mets, hypercalceemia with mets not responsive to other treatment.

27
Q

Denosumab MOA

A

Subcut 6 monthly. Can also give in prostate ca or breast with mets

Reduces osteoclast formation and differentiation by being a monoclonal Ab against RANKL

28
Q

Raloxifene MOA

A

SERM

29
Q

strontium ranelate MOA

A

increase osteoblast reduce osteoclast activity

30
Q

Teriparatide MOA

A

Synthetic PTH

PTH paradox says that initial increase in bone formation (up to 18 months) followed by bone reabsorption

31
Q

Vitamin D effect on bone

A

Increase RANKL expression

32
Q

Calcitonin effect on bone

A

interacts directly with osteoclasts to inhibit activity

33
Q

Oestrogen bone effect

A

decrease in RANKL

34
Q

Steroid effect on bone

A

predominantly cancellous bone loss

especially accelerated in first twelve months of treatment

35
Q

What bad things does combined HRT increase risk of?

A
Breast cancer
DVT
Dementia
Stroke
PE
gallbladder disease
urinary incontinence
36
Q

Who do we say should get calcium and vit D supplementation>

A

On antiresorptives
Steroids over 7.5mg/day
Elderly or housebound
Insufficient dietary intake

Post men women and men over 70 should be getting 1300mg/day dietary
Others 1000mg/day dietary

37
Q

What markers of osteoblast activity?

A

Bone specific ALP
Osteocalcin
P1NP (collagen synthesis)
PICP

38
Q

What reflects bone resorption?

A

N-TELOPEPTIDE in urine
C-TELOPEPTIDE in serum

Increase in low BMI and smoking
Can check if suspect non compliance with antiresoprtive to see has it gone down 30-50%

39
Q

Menopause effect on bone?

A

Accelerated phase of trabecular bone loss with trabecular fperforation and loss of connectivity

This is followed by a slower phase that happens in both men and women of CORTICAL loss

The most consistent finding in men ane women is decrease wall width

Bone loss in older men is associated with trabecular thinning rather than perforation

40
Q

Effects of calcitonin

A

inhibits intestinal calcium reabsorption
inhibits osteoclasts stimulates osteoblats
inhibit renal calcium AND phosphate reabsorption

41
Q

Which medications cause hypercalcaemia?

A

Thiazides
Lithium
Viramin D
Calcium carbonate

42
Q

What are the complications of primary hyperparathyroidism?

A
Osteoporosis and fractures
Brown tumour formation
Osteitis fibrosa cystica
Subperiosteal bone resorption
Distal clavicles tapered
Salt and pepper skull
43
Q

Should you replace vitamin D before parathyroidectomy?

A

Yes- reduced risk hungry bone syndrome

44
Q

Most common cause of hypercalcaemia of malignancy?

A

PTHrP without bony mets responsible 80% of time
OSteolysis 20% time
Occasionally ectopic PTH or 1,25 dihydroxyvitamin D

45
Q

Effect DM on BMD

A

type 1 reduce

type 2 increase