Osteoporosis Flashcards
What is osteoporosis
- Low bone density + impaired bone structure
- Primarily effects females >50 years old and increasing with age
What is a T-score
- Measured bone mineral density to average peal BMD of health, young adult of same sex and ethnicity
What do the T-scores represent
DEXA will be used to measure BMD
1. Negative at or above -1 = denser bones
2. Normal > or equal to 1
3. Osteopenia = -1 to 2.4
4. Osteoporosis = <-2.5
What is FRAX
Fracture Risk Assessment Tool (FRAX)
1. Estimates osteoporotic fracture risk in the next 10 years
*plus other major bones
What are the medications that can worsen osteoporosis
- Anticonvulsants
- Select antiretroviral therapy
- Canagliflozin *
- Heparin
- Glucocorticoids
- Furosemide
- Lithium
- Depo medroxyprogesterone
- Proton pump inhibitors
- SSRIs
- Excessive thyroid supplementation*
- Thizaolindinediones *
*key offenders
What is the etiology of osteoporosis
- Genetics
- Diet
- Lifestyle
- Hormonal
- Aging
Will cause bone loss, then impaired bone quality and decreased bone density which leads to low trauma fractures
What are osteoblasts and osteoclasts
blasts = bone formation
Clasts = bone resorption
How is OPG (osteoprotegrin) related to osteoporosis
- OPG is stimulated by estrogen and inhibits RANKL
*RANKL is needed for osteoclast maturation - Estrogen is decreased in menopause
*which leads to a decrease of osteoclast formation and osteoporosis
What is WNT and Sclerostin
WNT (lipid modified glycoprotein)
1. Regulates proliferation and differentiation of stem cells
2. WNT is stimulated by PTH which signals to increase osteoblasts and bone build up
Sclerostin
1. Produced in osteocytes to stop bone formation
What is the influence of estrogen on osteoporosis
- Suppresses the proliferation and differentiation of osteoclasts
*will inhibit the breakdown of bone increase OPG - Increase osteoclast apoptosis
- Decrease production of RANKL
What is the influence of testosterone on osteoporosis
- Affects bone resorption
- Increases osteoblast differentiation and proliferation
What effects does estrogen have on osteoblasts and osteoclasts
Blasts
1. Decrease apoptosis
2. Decrease oxidative stress
*will have maintenance of bone formation
Clasts
1. Increase in apoptosis
2. Decrease RANKL
*decrease bone resorption
What is the pathophysiology of osteoporosis
Ages 30-45
1. Men and women lose bone at a similar rate
Post-menopause
1. Bone loss is accelerated due to decrease in estrogen
What happens when calcium levels are not maintained
- When increased calcium absorption / reabsorption is not enough to maintain adequate calcium levels = bone resorption
What is the diagnosis criteria for osteoporosis
- Previous Low trauma fracture
*hip or spine regardless of BMD - T-score at or below -2.5
- T-score between -1 and -2.5 with fragility fracture
- T-score between -1 and -2.5 with high FRAX probability
What is the most appropriate prevention therapy for osteoporosis (Younger, health postmenopausal women)
- Estrogen alone (if no uterus)
*bisphosphonate (used if estrogen is CI)
*Raloxifene (for postemenopausal women with an elevated risk of breast cancer)
What are bisphosphonates used for
- To prevent bone loss
- For women with low BMD scores <-1
- Used for who do not meet criteria for osteoporosis treatment
When are medication recommend to prevent bone loss in postmenopausal women
- Premature menopause
- Low BMD (T-score <1.0)
- Low BMD score and other risk factors for fracture
What is the primary goal of prevention of osteoporosis
- Optimize calcium and vitamin D intake
- Regular exercise
- Ensure proper body weight
When should osteoporosis treatment be considered
Postmenopausal women/men aged 50 or older with
1. Hip or vertebral fracture
2. Central DXA t-score of -2.5 or lower
3. Osteopenia with a 10 year FRAX of 3% or more
4. Osteopenia with a 10 year FRAX of any major osteoporitc related fracture of 20% or more
What are some non pharmacological treatments of osteoporosis
- Adequate calcium and vitamin D
- Reduce alcohol
- Reduce caffeine
- Smoking cessation
- Weight bearing exercise
- Fall prevention
What are the first line agents of osteoporosis treatment
Always take with vitamin D and calcium
Bisphosphonates
1. Alendronate (fosamax)
2. Risedronate (Actonel)
3. Zoledronic acid
Denosumab
What are some alternative therapies for osteoporosis
- Raloxifene
- Ibandronate
- Teriparatide
- Abaloparatide
- Romosozumab
What are the ADRs and drug interactions of calcium supplementation
ADRS
1. Constipation
2. Kidney stones
Drug interactions
1. PPIs may decrease absorption
2. Calcium can decrease absorption of many medications
What is the recommend doses for calcium supplementation
- Should not exceed 500 to 600 mg (BID) of elemental calcium
*total 1,200mg elemental calcium per day (post-menopausal women)
What is the dosing recommendation and drug interactions of vitamin D
Dose = 1,000 units
Drug interactions
1. Can increase absorption of aluminum
What is the MOA of Bisphosphonates (oral)
Inhibits osteoclasts activity and bone resorption
What are the dosing schedule of bisphosphonates (oral)
Dosing varies if prevention, treatment or glucocorticoid induced OP
1. Alendronate (fosamax)
*daily but varies if female is taking estrogen
*combination with cholecalciferol available
2. Risedronate (actonel)
*daily, weekly, monthly
3. Ibandronate (boniva)
*monthly, only decreases vertebral fx
What are the CI OF oral bisphosphonates
- Hypocalacemia
- Inability to stay or sit upright for at least 30 minutes