Osteoporosis Flashcards
What is a T score
stand deviations from mean peak bone density of a normal young adult
What is a Z score
standard deviations from reference population of the same age, sex, and ethnicity
If z score <2.0 evaluate for secondary causes
What are risk factors for osteoporosis (18)
Personal hx of fracture
1st degree relative with fx
Caucasian
Current smoker
Lifelong low Ca intake
Poor eyesight or fall risk
Vit D deficiency
Inadequate physical activity
Age/frail
BMI <20, weight <127lbs
Renal impairment
Hyperparathyroidism
Estrogen deficiency
Alcohol (>3 drinks/d)
Hypocalcemia
Gastric bypass
RA
Drugs (anticonvulsants, steroids, chronic heparin, tamoxifen, aromatase inhibitors, DMPA, antiretroviral drugs, TPN, lithium)
What are prevention recs of osteoporosis
Routine mod-high aerobic activity and weight bearing exercises
Consume Calcium
- Age 9-18: 1300mg Ca/d
- Age 19-50: 1000mg Ca/d
- Age >50: 1200mg Ca/d
Consume Vit D
- Maintain Vit D at 20
- 600 IU/d until 70
- 800 IU/d after 70
Fall prevention
How do you screen for osteoporosis
Age >65 yo every 2-8 years
Postmenopausal women <65 if FRAX score >8.4%
If initial BMD is near tx thresholds or if new risk factors, repeat DEXA no sooner than 2 years
What is a normal T score
-1.0 or higher
What is diagnosis of low bone mass
T score between -1.0 and -2.5
What is the diagnosis of osteoporosis
T score less than -2.5
When do you treat bone density abnormality
T score >-2.5 (osteoporosis)
T score -1 to -2.5 if FRAX score is abnormal
- 20% any, 3% hip
Postmenopausal women with a fragility fracture
- If >1.5 in height loss from peak height at age 20, get Xray to r/o vertebral fracture
Before starting Tx, evaluate for secondary causes
What is the lab work up for osteoporosis/penia
CBC
CMP (Ca, renal fx, phosphorus, magnesium)
Vitamin D
24hr urinary calcium, sodium and creatinine excretion
TSH
PTH
What is the tx for osteoporosis
Bisphosphonates: First line
MOA: inhibits bone reabsorption by osteoclasts
Contraindications: esophageal abnormalities, reflux, renal failure
May cause osteonecrosis of the jaw and atypical femur fractures, consider drug holiday after 5 years or 3yrs if IV
What are other treatments for osteoporosis
Selective estrogen receptor modulators: Raloxifene
- Pro-estrogenic in the bone and anti-estrogenic on endometrium
Rank ligand inhibitor
- Monoclonal antibody
- SQ injection q6 months
- CI with hypocalcemia
Calcitonin (rarely used)
- binds to osteoclasts and inhibits bone resorption
- 200 IU/d intranasal
Anabolic therapies for high risk pts
- PTH hormone–> stimulates bone formation, SQ injection
- Sclerostin inhibitor–> monoclonal antibody, SQ inj, CI: hypocalcemia, MI or stroke in previous year
How do you monitor osteoporosis while on treatment
DXA q1-3 yrs until BMD stable
Check renal fx, vit D and serum calcium q 1-2 yrs
If progressive loss or new fx consider inciting factors
Refer to specialist if T score is -3.0 or worse, recurrent fx or loss of BMD on medications, comorbidities, metabolic causes
What is the difference between tamoxifen and raloxifene
Tamoxifen
- Can cause endometrial thickening
- increased risk of VTE
- 50% reduction of breast cancer
- increased BMD
Raloxifene
- Used for osteoporosis and breast cancer
- Does not increase risk of endometrial cancer
- increased BMD
- 60% reduction of breast cancer
