Osteoporosis Flashcards
What is osteoporosis?
progressive decrease in bone mass that results in increased bone fragility and a higher fracture risk
-loss of bone mass and bone strength
bone mineral density > 2
What is osteopenia?
low bone density with bone mineral density (BMD) between -1 and -2.5
What is primary osteoporosis?
-idiopathic (80% of women and 60% of men with osteoporosis
What is stage 1 primary osteoporosis?
- occurs in post-menopausal women
- accelerated trabecular bone loss
- vertebral body and distal forearm fracture
what is stage 2 primary osteoporosis?
- both men & women >70;
- trabecular and cortical bone loss;
- fractures of proximal humerus, proximal tibia, femoral neck, and pelvis
What is secondary osteoporosis?
- common feature of another disease process
- inheritable disease of connective tissue or drug side effect -(Affects 20% of women and 40% of men)
What are some risk factors of osteoporosis?
- 5x increase each decade after 40
- family hx of hip fracture
- Ethnicity: whites > asians & hispanics > blacks > polynesians
- poor nutrition (calcium deficiency)
- physical inactivity
- meds (chronic corticosteroid use, anticonvulsants, anticoagulants)
- tobacco, alcohol
- high caffeine intake
What are some chronic disease states that can increase a patients risk of osteoporosis?
- estrogen deficiency
- androgen deficiency
- hyperparathyroidism
- IBS
- diabetes
- hypercortisolism
- cirrhosis
- malabsorption
- gastrectomy
- multiple myeloma
what is the most important influence on bone density?
hereditary
when does bone mass peak?
beginning of third decade
which peaks first in bone mass density:
- skeletal/appendicular, or
- spine/axial?
skeletal/appendicular (ages 18-20)
spine/axial peaks at ages 25-30
Bone modeling, an increase in bone mass and size, is done through what?
Endochondral ossification of the axial skeleton
Periosteal application of the appendicular skeleton
bone remodeling is the process of?
bone resorption and subsequent formation that results in repair of damaged bone
Bone remodeling provides what to the systemic circulation?
calcium
The cellular apparatus that facilitates remodeling is the B<u></u>
- bone resorbing osteoclasts
- bone forming osteoblasts
- bone lining cells
- embedded osteocytes
In a BMU, the first 10-20 osteoclasts resorb old or damaged tissue. they then recruit how many osteoblasts to produce new bone matrix?
1000-2000 osteoblasts
osteocytes account for what percent of bone cells?
90-95% cells
osteocyte activity produces active release of
cytokines (RANKL and OPG) for osteoclast development
the balance of RANKL and OPG cytokines determine what?
the rate of bone resorption
how does paget’s disease affect bone structure?
it is abnormal bone formation
how does the loss of estrogen increase resorption of bone?
- increases upregulation of cytokines (RANKL)
- decreases OPG production (inhibits resorption)
why is there a slower rate of bone loss in older obese women?
estrogen stores in adipose tissue
Low vitamin D (25-hydroxy) can acelerate bone loss but can also result in what?
secondary hyperparathyroidism
What are the signs and symptoms of osteoporosis?
commonly none, can have dorsal kyphosis (dowagers hump) and loss of height
what are the most common fractures associated with osteoporosis?
spine/vertebral fractures
kyphosis (dowagers hump) is due to
vertebral fractures
what type of fracture has a risk that increases exponentially with age?
proximal femur - costly! usually due to a fall
what fractures are common prior to age 60, but then decreases in risk
- distal forearm (esp: Colles)
- proximal humerus
- pelvis
what might a patient complain about with a spinal fracture?
- may or may not have pain
- fell and heard a “pop” followed by sharp midline back pain
- back is “tired” and feels better when they sit or lie down
what percent of women with type 1 osteoporosis have associated secondary causes?
20%
what measured height loss suggests a vertebral fracture?
> 4 cm
how is the diagnosis of osteoporosis made?
bone mineral density (BMD)
what does DEXA stand for?
Dual-Energy X-ray Absorptiometry
who should get a bone density test (bone densitometry)?
- all women over 65
- all women under 65 with risk factors (weight under 127 lbs, parental history of hip fracture, use of medication that causes bone loss, smokers, alcoholics, or RA)
DEXA scores are called T scores; what are the scores for:
- normal
- osteopenia
- osteoporosis
- normal: above -1
- osteopenia: -1 to -2.5
- osteoporosis: below -2.5
lower T-scores reflect ______ bone density
lower
what does a Z score do?
compares bone density to what is normal for someone of comparable age and body size; can be misleading
what is a normal Z score?
above -2
for whom do experts recommend using a Z score for?
- children
- teens
- women still having periods
- younger men
repeat BMD testing for women with normal bone density of mild osteopenia
10-15 years
repeat BMD testing for women with moderate osteopenia
3-5 years
repeat BMD testing for advanced osteopenia
annually
most DEXA cannot measure BMD in patients weighing more than
300 lbs; try peripheral BMD of forearm or heel
other screening tests for BMD?
- PDXA (peripheral dual energy xray absorptiometry)
- QUS (quantitative ultrasound)
- PQCT (peripheral quantitative computed tomography)
what other imaging tests can help evaluate bone health?
nuclear bone scans
- CT scans
- MRIs
What are some lab tests you can run?
- serum BMP (eval for renal and hepatic function)
- parathyroid hormone levels
- CBC (nutritional status)
- thyroid function tests
- 25-hydroxyvitamin D
- serum calcium
- 24 hr urine for calcium
- testosterone for men
what are 2 bone resorption markers that can be found on biochemical marker tests in relation to bone density?
- NTX: N-telopeptide cross links
- CTX: C-telopeptides
are the levels of resorption markers high or low in high turnover osteoporosis?
high
are the levels of resorption markers high or low in low-normal turnover osteoporosis?
low or normal; no accelerated bone loss
what type of therapy does high turnover osteoporosis respond best to?
anti-resorptive therapy
what type of therapy does low turnover therapy respond best to?
drugs that enhance bone formation
do most premenopausal women with low bone density have an increased risk of breaking a bone?
no
are osteoporosis medications approved for premenopausal women?
no
if a pregnant mother doesn’t have enough calcium to meet the fetus’ needs, what will the fetus do?
take it from her bones
does pregnancy associated osteoporosis go away?
yes, it’s rare and goes away shortly after birth
does having more children increase a woman’s chances of getting osteoporosis?
no, actually the opposite, it can help protect the woman from osteoporosis and broken bones
can breast feeding cause bone loss?
yes but it’s temporary
what are some common ways to help prevent bone loss?
- minimize risk factors
- stop smoking
- resistance and high-impact exercise
- supplemental calcium and vitamin D
what are some first line treatments in women that can help combat osteoporosis?
- supplemental calcium
- supplemental vitamin D
- bisphosphonates
- denosumab
women 19-50 and men 19-70 can take how many mg of supplemental calcium?
1000 mg
women over 50 and men over 70 can take how many mg of supplemental calcium?
1200 mg
amount of supplemental vitamin D age 19-70
600 IU/day
amount of supplemental vitamin D age 71+
800 IU/day
how do bisphosphonates help to decrease bone loss?
decrease bone resorption by decreasing osteoclast activity
ibandronate: monthly; alendronate, risedronate: weekly; zoledronic acid IV: yearly
how does denosumab (monoclonal antibody) help to decrease bone loss?
decreases bone resorption by inhibiting formation and activity of osteoclasts
(60 mg every 6 months)
what are some second line treatments to help combat osteoporosis in women?
- parathormone (daily injection)
- selective estrogen receptor modulators (raloxifine)
what are some last line treatments to help combat osteoporosis in women?
- calcitonin
- HRT/ERT (sig. cardiac risk)
- combination estrogen/alendronate or estrogen-progestin/alendronate
what are some FDA approved treatments for women to combat bone loss even if they don’t have an indication of osteoporosis?
- calcitriol (stimulates calcium and phosphorus absorption)
- etidronate (paget’s disease or hypercalcemia; inhibits osteoclast activity)
- thiazide
who is more likely to die within a year after breaking a hip, men or women?
men, due to problems related to the break
what are some risk factors for osteoporosis in men?
- hypogonadism
- hyperthyroidism
- GI disorders
- anticonvulsant meds
- excess alcohol intake
- hypercalciuria
- immobilization
- glucocorticoid therapy
what is primary treatment for osteoporosis in men?
-supplemental calcium and vitamin D
what are some other treatments for osteoporosis in men?
- bisphosphonates
- parathyroid hormone
what body parts should be evaluated by the DEXA?
- hip
- spine
- wrists
