Osteoporosis Flashcards
What is osteoporosis
low bone density (weak bones) leading to increased fracture risk
Why do men and women start losing bone density in 3-4 decade
Women: Menopause= estrogen deficiency= increased osteoclast activity= bone resorption>formation
Men: aging and secondary causes; occurs later 2/2 larger bone size and mass
What can all individuals do to reduce risk of osteoporosis
Incorporate healthy bone lifestyle from birth
Regular exercise, nutritious diet, avoid tobacco, minimize alcohol consumption
Fall prevention
RF of osteoporosis are
age, Hx of fracture, glucocorticoids, parent Hx of hip Fx, low body weight, cigarette smoking, excess alcohol, RA
Secondary osteoporosis RF are
hypogonadism premature menopause malabsorption chronic liver disease IBD
Age related osteoporosis results from
hormone, calcium, and vitamin D deficiency
leads to accelerated bone turnover and reduced osteoblast formation
Drug induced osteoporosis results from
systemis corticosteroids, thyroid hormone replacement, AED (phenytoin, phenobarbitol), depot medroxyprogesterone acetate
What is the FRAX tool
WHO created tool to assess probability of Fx in the next 10 years
-age, race, sex, Hx of fragile fx, BMI, glucocorticoids, current smoking, alcohol (3+/day), RA, femoral neck or total hip bone mineral density
What is the Garvan calculator
Uses 4 RF (age sex low trauma Fx and falls) +/- BMD to calculate 5 and 10 year risk estimates
Better than FRAX bc it includes falls and # of previous Fx instead of a bunch of other random RF
What is the standard diagnostic test fro BMD
DXA (dual energy x-ray absorptiometry)
Diagnosis of osteoporosis is based on
low trauma Fx OR
central hip/spine DXA using WHO T-score threshold
*For kids, pre-menopause women, and men <50, Dx based on Z score
What are T scores indicative of
Osteopenia (low bone mass): -1 to -2.5
Osteoporosis: Less than -2.5
(T scores applied to perimenopausal women, men 50+, and other races)
Absorptive therapies (keep it in the bone) include
*Calcium
*Vitamin D
**Bisphosphanates
calcitonin
Estrogen agonists
Estrogen
Testosterone
Teriparatide
Denosumab
What age group needs the most calcium and vitamin D
9-18 years old
What are the tow forms of calcium
- Calcium carbonate (can cause bloating, gas, constipation, hypercalcemia, hypophosphatemia; rarely, stones)
- Calcium citrate (hypercalcemia, hypophosphatemia)
What are the forms of vitamin D
D3: Cholecalciferol (not active, natural form)
D2: Ergocalciferol (plant derived)
D: Calcitriol, AKA 1,25 OH vitamin D (active)
When would you need to increase the dose of D3 (cholecalciferol)
In malabsorption
If taking anticonvulsants (carbamazepine, phenobarb, phenytoin)
What are the ADE of D3 (cholecalciferol)
Hypercalcemia (HA, weakness, cardiac disturbance)
Hypercalcuria
When would you Rx Ergocalciferol (D2)
if Vitamin D deficient
How is Calcitriol formed
D3 is hydroxylated in the liver and other tissues to make calcifediol (25 OH-D)
That is then metabolized in the kidneys to make calcitriol
Indications for using exogenous Calcitrol
renal osteodystrophy
hypoparathyroid
refractory rickets
What are the bisphosphanates (first line for osteoporosis)
Alendronate
Risedronate
IV Zoledronic acid (Reclast) (IV infusion q2 years)
(first line for post-menopause women, man and glucocorticoid induced osteoporosis)
-IV and oral Ibandronate only for post-menopausal women
What is the MOA of bisphosphonates
Mimic pyrophosphate (endogenous bone resorption inhibitor)= decrease osteoclast maturation, #, recruitment, and life span Half life is up to 10 years (becomes incorporated into bone)
Important notes for each bisphosphonate
Alendronate: Take in AM on empty stomach w/ 6=8 oz water. Dont eat and Stay upright for 30 min. Dont take w/ any other supplements
Ibandronate: same as Alendronate, but stay upright for 60 min
Risendronate: Same as Alendronate, but ER tab (Atelvia) is taken right AFTER breakfast
Zoledronic acid: DO NOT take if CrCl <35
