Osteoporosis Flashcards
What is osteoporosis?
microarchitectural deterioration of bone tissue leading to decreased bone mass
bone fragility
susceptibility to fracture
a problem of decreased peak bone mass and accelerated bone loss
affects 10 million in the US
When does it get harder to add bone mass?
Reach full genetic potential around 18-20. After that you hold steady until menopause. Inadequate lifestyle factors (smoking, poor diet, etc) will affect your potential.
What is a central DXA measurement?
gold standard for measuring bone mass
measures multiple skeletal sites: spine, proximal femur, forearm, total body
office based
considered clinical standard
What is a T-score?
number of standard deviations from the young adult mean density
osteoporosis= T score -2.5 or less
osteopenia= T score -1 to -2.5
For every standard deviation below the norm….
fracture risk doubles
What is a Z-score?
number of standard deviations from age matched mean density
accounts for age
apply to pre-menopausal females and males <50
What is the FRAX?
WHO fracture risk assessment tool
treatment decision making tool in previously untreated patients
calculates 10 year fracture risk: hip fracture, major osteoporotic fracture (spine, forearm, hip, shoulder)
What is primary osteoporosis?
unrelated to chronic illness
related to aging and decreased gonadal function
What is secondary osteoporosis?
secondary to chronic illnesses/meds that cause accelerated bone loss
examples- glucocorticoid use, hyperthyroidism
What are osteoporosis risk factors?
genetics, low calcium intake, low vitamin D stores, tobacco and alcohol use, prior history of fracture, medications, malabsorption, excessive urinary calcium, overactive thyroid, other medical conditions
What are options for secondary evaluation of osteoporosis?
comprehensive metabolic panel CBC 24 hour urine for calcium, creatinine, sodium 25-hydroxy vitamin D TSH SPEP/UPEP if anemic PTH
How can you assess fall risk?
Timed Get Up and Go Test (stand from seated, walk ~10 feet, turn around, return to seated position in chair)
normal time <10 seconds
good objective measure to have documented
How can your lifestyle affect bone health?
adequate calcium intake (diet + supplement ~1200 mg/day) optimal vitamin D levels (25OHD>32ng/mL) weight bearing exercise avoid tobacco use avoid excessive alcohol use
What are some dietary sources of calcium?
milk-300mg, yogurt-250mg, orange juice-300 mg, cheese-195-335mg, cottage cheese-130 mg, soy milk-100 mg, dark green leafy vegetables-50-135 mg
What are two sources of calcium?
Calcium carbonate: needs stomach acid for absorption (poorly absorbed if on PPI), taken with meals
Calcium citrate: can be taken with or without food, limit to 500 mg in dose, constipation
What are some vitamin D supplements?
vitamin D2: ergocalciferol
vitamin D3: cholecalciferol
25OHD lab value helps to guide supplement
can be taken with or without food
safe upper limit defined at 2000 IU
likely much higher: vitamin D3 10,000 IU/day up to 5 months
Natural ways to get Vitamin D?
Sunlight
sunscreen however inhibits formation of vitamin D
recommended to have 30-60 minutes of sun exposure
What are exercise recommendations for people with OA?
thirty minutes most days of the week
weight bearing exercise: running, walking, elliptical
muscle strengthening exercises
balance
What are examples of weight bearing exercises?
aerobics, circuit training, jogging, jumping, volleyball, walking
What are the effects of exercise on BMD in kids?
weight bearing increases BMD
gains over 6 months at hip and spine
range 1-6% before puberty
range of 0.3-2% during adolescence
What are effects of exercise on BMD in premenopausal women?
resistance training
high impact weight bearing exercise: produce 1-2% gains in BMD at spine and hip (resistance training>spine, high impact training>hip)
menstrual status effects these gains
What are the effects of exercise on BMD in older adults?
post-menopause: lumbar spine BMD can be increased by 1-2%, hip data somewhat contradictory
older men: 12 month trial of moderate weight bearing exercises 3xweek vs no exercise (2% net gain in femoral neck BMD)
Who gets referred to physical therapy
those at increased risk of fall
those with unstable gait
those with noted weakness: safe walking program, gait evaluation, lower extremity strengthening program
people with osteoporosis to get set up on a exercise program
What are the pharmacological treatments of Low bone mass?
bisphosphonates
teriparatide
denosumab
selective estrogen receptor modulators
What are the types of bisphosphonates?
alendronate (Fosamax): weekly
risedronate (Actonel): weekely, monthly
ibadronate (Boniva): monthly, IV every 3 months
zolendronic acid (reclast): IV annually
What is mechanism of action for bisphosphonates?
osteoclasts are targets
1) bisphosphonate attaches to exposed bone mineral surfaces
2) osteoclast takes up bisphosphonate which leads to loss of ruffled border, inactivation, detachment
3) new bone formation by osteoblasts renders bisphosphonate inert, inaccessible
What are side effects of bisphosphonates?
upper GI irritation, osteonecrosis of jaw, severe musculoskeletal pain, hypocalcemia, uveitis/scleritis, atypical femur fractures
What is teriparatide, and when should it be avoided as a treatment?
anabolic (bone building agent), SQ injection given daily
black box warning: osteosarcoma
Avoid if: Paget’s disease, elevation of bone alkaline phosphatase, open epiphyses, prior external beam radiation, prior implant radiation
What is denosumab and its MOA?
new agent, approved summer 2010: post menopausal osteoporosis
humanized monoclonal antibody against RANKL
inhibits osteoclast function
decreases bone resorption
consider in patients with kidney dysfunction
What are 3 other possible pharmacologic agents that are used for osteoporosis?
calcitonin: nasal spray or injection, decreased vertebral fractures, no hip fracture data
raloxifen: SERM, decreased vertebral fractures
estrogen replacement
Who should receive treatment?
those with osteoporosis
those with low bone mass: high risk medications (steroids, aromatase inhibitors, androgen deprivation therapy)
FRAX risk calculation: >3% hip fracture of next 10 years, >20% any osteoporotic fracture over next 10 years
How can you monitor bone health?
repeat bone density: every one to two years if on treatment, every two years if not on treatment but at risk for further bone loss
continuous re-evaluation of treatment needs
