ISCD Course Flashcards
What is the NIH consensus definition of osteoporosis?
A skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture
Bone strength reflects the integration of which two features?
- Bone density
- Bone quality
Does low bone mass have symptoms?
No
Unless a fracture occurs, then there is pain at fracture site
How is a fragility fracture defined?
Fracture from a fall from standing position or less.
Worldwide - what are the three ways osteoporosis can be diagnosed by?
- Fragility fracture
- T-score of -2.5 or less
- FRAX score with increased fracture risk
What are give functions of the skeletal?
- Supports the body
- Protects internal organs
- Muscles attached for movement
- Cavities for blood formation
- Reservoir for minerals
What region of the skeletal is included in the central skeletal?
Axial skeletal plus hips and shoulders
What region of the skeletal is included in the peripheral skeletal?
Appendicular skeletal minus the hips and shoulders
What kind of bone makes up the appendicular skeletal?
Cortical or compact bone
What kind of bone makes up the axial skeletal?
Cancellous or trabecular bone
What is osteomalacia?
A normal amount of bone that is inadequately mineralized
What percentage of the adult skeleton is remodelled at any one time?
10%
What is the turnover each year of cancellous bone?
25%
What is the turnover each year of cortical bone?
3%
What is the mass of cancellous bone?
20%
What is the mass of cortical bone?
80%
What is the surface area of cancellous bone?
80%
What is the surface area of cortical bone?
20%
What is bone modelling?
Change in size and shape of bone during growth
What is remodelling of bone?
Renewal of mature bone through:
- involves replacement of old bone with new bone
- occurs in response to fatigue damage, micro-fractures, and other fractures
How long is the bone remodelling cycle?
7 - 10 days
How long does osteoblast bone formation take?
10 - 12 weeks
What is the peak bone mass?
Peak bone mass is the maximum bone mass or density during a lifetime.
At what age do you have peak bone mass (after which it starts declining)?
30 years old
What is consolidation?
When growth in size of bones and accumulation of bone mineral has stabilised.
Peak bone mineral density:
Trochanter?
Mid-teens
14.2 +/- 2.0
Peak bone mineral density:
Femoral neck?
Late teens
18.5 +/- 1.6
Peak bone mineral density:
Spine?
Early 20’s
23 +/- 1.4
How much do heredity/genetics influence peak bone mass?
60 - 80%
Does gender influence peak bone mass?
Yes
What are the four nutritional factors influencing peak bone mass?
- Energy intake
- Protein intake
- Calcium intake
- Vitamin D
What are the three endocrine factors influencing peak bone mass?
- Sex steroids
- Calcitriol
- GH-IGF-1 axis
What are the two mechanical factors influencing peak bone mass?
- Physical activity
- Body weight
How fast does age-related bone loss occur?
~ 0.5 - 1.0% per year
How fast does bone loss occur after menopause?
~ 1 - 2% per year
Accelerated
What does a major BMD change in either direction require?
Evaluation for technical issues
Is post-menopausal osteoporosis common at age ~ 55 years (after about 5 years of menopause)?
No - it’s unusual.
Secondary causes must be sought.
Can you differentiate between osteoporosis or osteomalacia on DXA?
No
What should you think of if you have a 24 hour urine calcium
Celiac disease
What should you think of in a patient with unexplained iron deficiency and osteoporosis?
Celiac disease
What should you think of in a patient with irritable bowel symptoms and osteoporosis?
Celiac disease
What should you think of in a patient with decreased BMD, fractures or sustained high NTX/CTX despite oral therapies?
Celiac disease
How do you screen for celiac disease?
Tissue transglutaminase IgA antibody
What is the sensitivity of transglutaminase IgA antibody for Celiac disease?
> 90%
What is the specificity of transglutaminase IgA antibody for Celiac disease?
> 95%
Falsely negative transglutaminase IgA antibody screening for Celiac disease may occur in case of IgA deficiency.
True or false?
True
What percentage of Celiac disease patients have IgA deficiency?
2 - 3%
In what two situations may the transglutaminase IgA antibody screening for Celiac disease be falsely negative?
- IgA deficiency
- Mild disease
What is the gold standard for celiac disease diagnosis?
- Duodenal biopsy
What is the treatment of osteoporosis caused by celiac disease?
- Gluten-free diet
- Calcium and vitamin D supplementation
Are oral bisphosphonates preferable in patients with malabsorption issues?
No
What view is VFA?
Lateral or PA?
Lateral view
What does VFA stand for?
Vertebral fracture assessment
When should VFA or spine imaging be obtained?
When fracture status would alter therapy.
By approximately how much does 1000 IU of vitamin D raise the serum vitamin D levels?
6 - 10 ng/dL
How soon after repleting vitamin D should the level be repeated?
~ 3 months
Should pharmacologic therapy for osteoporosis be delayed if vitamin D level is between 20 - 30 ng/mL?
No
What is the criteria for treating post menopausal women and men over 50 years on chronic steroids equivalent to prednisone of 7.5 mg a day or greater?
They require treatment.
What is the criteria for treating post menopausal women and men over 50 years on chronic steroids equivalent to prednisone of 7.5 mg a day or less?
If the FRAX is 10% or less they don’t require treatment; if the FRAX is more than 10% they require treatment.
What is the criteria for treating pre-menopausal women (non-childbearing) and men under 50 years on chronic steroids equivalent to prednisone of 5 mg a day or greater?
Treat only if they have a fracture.
What is the criteria for treating pre-menopausal women (childbearing) on chronic steroids equivalent to prednisone of 7.5 mg a day or greater?
Treat only if then have a fracture
When is lateral spine imaging (radiography or VFA) indicated?
- Women aged 70 or more; men aged 80 or more
- Historical height loss > 4 cm (1.5 inch)
- Self reported but undocumented prior vertebral fracture
- Glucocorticoid therapy equivalent to more than or equal to 5 mg of prednisone per day for 3 or more months.
What is the sensitivity of serum protein electrophoresis (SPEP)?
82%
What is the sensitivity of serum immuno-fixation (IPEP)?
93%
What is the sensitivity of serum and urine IPEP?
97%
Persistently low serum phosphate leads to inadequate bone mineralization and osteomalacia.
True or false?
True
Name three causes of decreased phosphate.
- Renal phosphate wasting due to excess FGF-23
- Malabsorption
- Malnutrition
Name two causes of phosphate wasting due to excess FGF-23.
- Genetic mutations
- Mesenchymal tumors
What syndrome can a small, slow-growing mesenchymal tumor secreting FGF-23 cause?
Acquired paraneoplastic syndrome
Clinical features:
- Progressive muscle and bone pain
- Weakness
- Fatigue
- Multiple fractures
- Low phosphorus
Diagnosis?
Tumor-Induced Osteomalacia
Acquired paraneoplastic syndrome caused by small, slow-growing mesenchymal tumors secreting FGF-23.
What does laminectomy do to spine BMD?
Lowers it.
If you’ve already treated a patient with a few years of zoledronic acid then what drug could you consider next…?
Teriparatide
When can testosterone therapy be used to treat osteoporosis secondary to hypogonadism (in men)?
When the serum testosterone is below 200 ng/dL on two different occasions.
Is family history of osteoporotic fracture or fragility fracture a risk factor for low bone mass?
No - it’s a risk factor for osteoporotic fracture
Are falls a risk factor for low bone mass?
No - they are a risk factor for osteoporotic fracture
Is sarcopenia a risk factor for low bone mass?
No - it’s a risk factor for osteoporotic fracture
Is sarcopenia a risk factor for low bone mass?
No - it’s a risk factor for osteoporotic fracture
Is loss of height a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Is late age at menarche a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Is menopause a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Is time since menopause a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Is dietary calcium a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Is alcohol intake a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Are medications a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Are inflammatory diseases a risk factor for osteoporotic fracture?
No - it’s a risk factor for low bone density.
Are clinical risk factors good predictors of low BMD?
No
Does acromegaly cause osteoporosis?
We are not sure.
Do loop diuretics cause osteoporosis?
We are not sure
Does immobilization cause osteoporosis?
Yes
Does HIV/AIDS cause osteoporosis?
Yes
Does organ transplantation cause osteoporosis?
Yes
Does COPD cause osteoporosis?
Yes
Does anorexia cause osteoporosis?
Yes
Does malignancy cause osteoporosis?
Yes
How often is osteoporosis associated with secondary disorders?
~ 50% of the time
What does tryptase test for?
Mastocytosis
Increased bone resorption independently predicts fracture risk in post-menopausal women.
True or false?
True
Most vertebral fractures occur below ____.
T6
What are two problems with quantitative morphology?
- May over-diagnose abnormalities that are not fracture
- May under-diagnose mild end-plate deformities
How and how often should height be measured?
Annually, preferably with a wall mounted stadiometer.
Trabecular bone - age related bone loss differs between men and women…
Women?
Perforation
Trabecular bone - age related bone loss differs between men and women…
Men?
Thinning
Name the three main sites of osteoporotic fractures starting with most common to least common.
- Vertebral fractures
- Hip fractures
- Distal forearm fractures
What percentage of hip fracture survivors are permanently incapacitated?
~ 50%
What percentage of hip fracture survivors require long-term nursing home care?
~ 20%
Is the radius or the ulnar used for BMD measurement in the forearm?
Radius
Does a T-score of less than -2.5 always mean that the patient has osteoporosis?
No
Name five examples of non-osteoporotic causes of low BMD.
- Osteomalacia
- Genetic disorders e.g. osteogenesis imperfecta
- Renal bone disease
- Multiple myeloma / other malignancies
- Marrow infiltrative diseases e.g. mastocytosis
What does it mean if the T-score goes down but Z-score stays the same?
The patient lost as much bone density as was expected.
Is the diagnosis of osteoporosis based on the mean T-score value or the lowest value?
The lowest value
Fracture risk increases exponentially with declining BMD.
True and false?
True
Should FRAX be used to monitor treatment response?
No
How long should a patient not have had estrogen therapy / hormone therapy to be considered ‘untreated’v
One year
How long should a patient not have had calcitonin to be considered ‘untreated’?
One year
How long should a patient not have had PTH to be considered ‘untreated’?
One year
How long should a patient not have had denosumab to be considered ‘untreated’?
One year
How long should a patient not have had bisphosphonates to be considered ‘untreated’?
Two years
Taking oral bisphosphonates for less than two months is okay.
How long should a patient not have had calcium and vitamin D to be considered ‘untreated’?
Calcium and vitamin D do not count as treatment in this regard.
If you have serial studies on the same machine should you compare T-scores or BMD?
BMD
What is the minimum acceptable precision error (LSC) for an individual technologist for…
Lumbar spine?
1.9% (LSC = 5.3%)
What is the minimum acceptable precision error (LSC) for an individual technologist for…
Total hip?
1.8% (LSC: 5%)
What is the minimum acceptable precision error (LSC) for an individual technologist for…
Femoral neck?
2.5% (LSC = 6.9%)
Which precision error should be used if there are multiple technologists at a center?
The average precision error for all the technologists is used
How is a precision analysis done?
Measure 15 patients 3 times, or 30 patients 2 times, repositioning patients after each scan.
Does precision assessment require IRB approval?
No
What is least significant change?
The precision error at a center ~ desired confidence level 95%
How is LSC calculated?
LSC = (precision error) x 2.77
to have 95% confidence that the change is real
