Flashcards in Osteoporosis Deck (40):
Is osteoporosis often silent?
Is just the density of the bone affected in osteoporosis?
No. Quality is decreased as well.
How many US men and women will have an osteoporosis-related fracture in their lifetimes?
1 in 2 women.
1 in 5 men.
What factor contributing to bone strength do we measure?
Density, with DXA.
Two main causes of low bone density late in life?
Low peak bone mass - never built it up.
4 lifestyle factors that contribute to osteoporosis?
Low calcium intake
Vitamin D deficiency
EtOH intake > 3 drinks/day
2 significant genetic risk factors for osteoporosis?
Family Hx of hip fractures.
3 endocrine disorders that contribute to osteoporosis?
(there are many others - Cushing's, DM, hyperprolactinemia, etc.)
Main GI disease to screen for related to osteoporosis?
Most important (according to highlighting) hematologic disorder related to osteoporosis?
Why does end stage renal disease (ESRD) contribute to osteoporosis?
Impaired Vitamin D activation.
Does rheumatoid arthritis contribute to osteoporosis?
5 medications that cause osteoporosis?
Osteoporosis diagnosis is only given to what demographic?
Men over age 50.
What part of the DXA scan results matters for osteoporosis diagnosis? What is the cut-off for diagnosis of osteoporosis?
Cut-off = -2.5
What is the T-score in DXA scans?
Number of standard deviations away from average bone density of young adults.
What is the Z-score in DXA scans?
# of standard deviations away from average bone density of age-matched controls.
What areas are usually scanned in DXA?
Lumbar spine, total hip, femoral neck (and sometimes forearm).
What T-scores for DXA are in the normal range?
-1 to 1
What's a T-score of -1 to -2.5 called?
What gives a osteoporosis diagnosis a designation as "severe"?
Having had a fracture.
How can you diagnose osteoporosis without a DXA scan?
History of "low-trauma" fracture.
Do the majority of fractures happen in people with osteoporosis?
No. (hip fractures in women do, though)
(...is this just because there are more people with osteopenia and normal bone density???)
7 risk factors in the Fracture Risk Assessment Tool (FRAX)?
Family Hx of osteoporotic fracture
What's the main utility of FRAX?
To decide if people in the "osteopenic" (i.e. not quite osteoporosis) category should get treatment.
3 reasons why you would pharmacologically treat post-menopausal women and men over 50?
DXA scan T score of -2.5 or less.
History of hip or spine fracture.
FRAX score >20% for all fractures or >3% for hip fracture.
4 non-pharm treatment to reduce fracture risk?
Reduce risk factors.
Take calcium and Vitamin D.
Reduce fall risk.
What are the 2 mechanisms by which bone density increasing drugs work?
Inhibiting osteoclast activity.
Increasing osteoblast activity.
What's the one drug that works to stimulate osteoblasts?
Teriparatide (recombinant PTH)
5 drugs that inhibit osteoclast activity?
Selective estrogen receptor modulator (SERM)
What main molecule promotes osteoclast activity? (What cell makes it?)
What endogenous molecule blocks the activity of that molecule? (What cell make that?)
RANKL activates osteoclasts. (made by immature osteoblasts)
OPG (osteoprotegrin) blocks RANKL. (Made by mature osteoblasts -recall from CTB that it's basically soluble RANK, the receptor for RANKL)
How do bisphosphonates work?
Bind to bone... preventing osteoclasts from working. Apparently the osteoclasts die, too.
Adverse effect of bisphosphonates? (short-term and long-term)
Short-term: GI discomfort - ulcers, constipation (oral). Increase in creatinine (IV). Flu-like illness (IV).
Long-term: May actually weaken bones -> atypical femur fractures. Osteonecrosis of jaw.
Denosumab MoA? Adverse effects?
mAb that soaks up RANKL - effectively giving OPG.
Adverse effects: hypocalcemia (when works too well), infections and skin reactions.
What's the deal with giving Teriparatide (rPTH)?
You can give it for about 2 years, and there's a net increase in bone density. After 2 years, the stimulation of osteoclast activity exceeds the stimulation of osteoblast activity.
(We don't why this doesn't mimic hyperparathyroidism... it's interesting.)
Adverse effects of Teriparatide? Who is it not given to?
Hypercalcemia, nause, orthostasis stuff.
Osteosarcoma - seen in rats, never in humans.
It's not given to people with existing bone proliferative diseases, like Paget's.
Utility of calcitonin?
Good for acute fracture and pain. Not so good for prevention.
What's the SERM used for osteoporosis? Why is it such a cool drug? Adverse effects?
It's cool because it agonizes estrogen receptors in bone, but antagonizes in breast and uterus - reducing the risk of reproductive cancers.
Adverse effects: Thromboembolism, symptoms of menopause (hot flashes, etc.)
Is estrogen prescribed for osteoporosis these days?
Not much. The risks outweigh the benefits.