Osteoporosis Flashcards
What is osteoporosis?
Skeletal condition characterised by low bone mass/reduced bone density, deterioration of bone tissue and disruption of bone architecture; all of the above leaves to decreased bone strength and increased fracture risk.
Discuss the pathophysiology of osteoporosis
Bone resorption > bone deposition
State some risk factors for osteoporosis- think about modifiable and non-modifiable risk factors
Non-modifiable
- Age(>65yrs)
- Female (particularly being post-menopausal)
- Caucasian or south asian
- Family history
- History of low trauma fracture
- Rheumatoid arthritis
Modifiable
- Low body weight
- Premature menopause
- Calcium/vit D deficiency
- Inadequate physical activity/reduced mobility and activity
- Cigarette smokiing
- Excessive alcohol intake
- Iatrogenic e.g. corticosteroids, aromatase inhibitors, SSRIs, PPIs
Which categories of pts should you consider assessing for osteoporosis? (3)
- Women >65yrs
- Men >75yrs
- Younger pts with risk factors
What tool is used to assess someones risk of osteoporosis?
FRAX tool
- Prediction of risk of fragility fracture in next 10yrs
- Uses information such as:
- Age
- BMI
- Co-morbidities
- Smoking
- Alcohol
- Family history
- Result from DEXA scan (don’t have to enter this so can use tool without DEXA scan)
-
Gives result as % 10 year probability of a:
- Major osteoporotic fracture
- Hip fracture
What would be the next step following if you do a FRAX assessment without DEX and the result is:
- Low risk
- Intermediate risk
- High risk
- Low= reassure
- Intermediate= offer DEXA and recalculate with results
- High= offer treatment
What is the main investigation you want to do for a pt with suspected osteoporosis?
DEXA scan (dual energy x-ray absorptiometry) which measures bone mineral density
Describe how a DEXA scan works
Results from which part of skeleton are most important in the classification and hence management of osteoporosis?
- Brief x-ray scan that measures how much radiation is absorbed by bone to indicate density of bone. Uses two low energy x-rays (one is absorbed by bone and one is absorbed by soft tissues)
- Better than normal x-ray because:
- More accurate for measuring bone density
- Lower radiation dose
- Can measure bone density at any location in skeleton but the reading at the hip is key
Bone density, obtained from a DEXA scan, can be represented as two scores. State the two scores and state what each score is
Which score is most clinically important?
- Z score: number of standard deviations below the mean bone density for their age and gender
- T score: number of standard deviations below the mean bone density of a person who is the same gender at age of peak density (25yrs)
T score is most clinically important as it is used in WHO classification of osteoporosis
Interpret the following T scores according to the WHO classification:
- > -1
- -1 to -2.5
- < -2.5
- < -2.5 + fracture
If a pt has a Z score of > -2, what should you be thinking?
*Remember, T score looks at number of standard deviations below mean density of bones of a healthy adult. Z score is numbe of standard deviations below mean density of bones of someone that age and gender.
Prompt evaluation of causes of secondary osteoporosis
A FRAX assessment with a DEXA scan will suggest two options; what are these options?
FRAX assessment with DEXA will either tell you to:
- Treat
- Give lifestylae advice and reassure
Discuss the management of osteoporosis, include conservative and pharmacological management
Conservative
- Weight bearing exercise
- Weight reduction
- Adequate calcium intake
- Adequate vitamin D
- Avoiding falls
- Smoking cessation
- Reduce alcohol
Pharmacological
-
Supplementation (always- even if levels adequete)
- Calcium
- Vit D
- 1st line= bisphosphonates (oral or IV if oral not tolerated)
- 2nd line= denosumab or teriparatide
- May also consider strontium ranelate
- If a woman is going through early menopause consider HRT or raloxifene
Describe the mechanism of action of bisphosphonates
Reduce osteoclast activity preventing reabsorption of bone
State some examples of bisphosphonates
- Alendronate (weekly, oral)
- Risedronate (weekly, oral)
- Zoledronic acid (yearly, IV)