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.
Explain the difference between the different types of osteoporosis, include:
- Primary osteoporosis: type 1 and type 2
- Secondary osteoporosis
Primary Osteoporosis
- Type 1: post menopausal women (generally women aged 50-70yrs)
- Type 2: age-associated “senile osteoporosis” (>70yrs)
Secondary Osteoporosis: due to underlying disease process, medications or lifestyle behaviours.
What’s the difference between osteoporosis and osteopenia?
Osteopenia= less severe reduction in bone density compared to osteoporosis
State some causes of secondary osteoporosis
Diseases/medical conditions
- Coeliac disease
- Eating disorders
- Cystic fibrosis
- Hyperparathyroidism
- Hyperthryoidism
- Multiple myeloma
Drugs
- Corticosteroids
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
- Caucasian or south asian
- Family history
- History of low trauma fracture
- Rheumatoid arhritis
Modifiable
- Low body weight
- Premature menopause
- Calcium/vit D deficiency
- Inadequete physical activity
- Cigarette smokiing
- Excessive alcohol intake
- Iatrogenic e.g. corticosteroids, aromatase inhibitors, SSRIs, PPIs
State some symptoms & signs of osteoporosis
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
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
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
- 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
Discuss the management of osteoporosis, include conservative and pharmacological management
Conservative
- Weight bearing exercise
- Weight reduction
- Adequete calcium intake
- Adequete 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)
State some side effects of bisphosphonates
- Reflux & oesophageal erosions
- Atypical fractures
- Osteonecrosis of the jaw
- Osteonecrosis of external auditory canal
Bisphosponates can cause reflux and oesphageal erosion; what instructions are given to pts to minimise this?
- Take on empty stomach
- Sitting upright for 30 mins before moving or eating
Compliance with bisphosphonates is poor; true or false?
True
Bisphosphonates are absorbed very well; true or false?
False, bisphosphonates are poorly absorbed
Describe the mechanism of action of denosumab
Monoclonal antibody that blocks osteoclast activity
Describe the mechanism of action of strontium ranelate
State some side effects
- Similar element to calcium that stimulates osteoblasts and inhibits osteoclasts
- Increases risk of DVT, PE, MI
Describe the mechanism of action of teriparatide
(parathyroid hormone analogue)
Discuss the follow up required for:
- Pts at low risk not given treatment
- Pts on bisphosphonates
- Low risk & not on treatment: lifestyle advice and follow up within 5yrs for repeat assessment
- Pts on bisphosphonates: repeat FRAX and DEXA after 3-5yrs and a treatment holiday should be considered if BMD has improved and they have not suffered any fragility fractures. Treatment break is 18months-3years before repeating assessment
State some potential complications of osteoporosis
- Fractures
- Treatment related ADRs as discussed
Vitamin D and calcium deficiency should always be corrected prior to starting bisphosphonates; true or false?
True
*NOTE: calcium supplements should only be given alongside bisphosphonates if intake inadequate. Vit D usually always given.
Discuss when we can consider a treatment holiday for bisphosphonates
