Osteoporosis Flashcards
- Porous bone (fragile bone disease), is a chronic, progressive metabolic bone disease characterized by low bone mass & structural deterioration of bone tissue, leading to increased bone fragility, increasing a pt’s risk for fx’s
1 in 2 women & 1 in 5 men >50 y.o. will sustain an osteoporotic fx & 50% of all postmenopausal women will sustain an osteoporotic fx
Osteoporotic hip fx’s cause mortality inc of 10-20% per year
Pathophysiology - Important factors that occur w/aging
- ↓ calcitonin
- ↓ estrogen
- ↑ PTH
Most freq noted areas of bone loss are assoc w/vertebral changes of L/S & hip fx’s & Colles fx of wrist
Clinical manifestations
- “silent disease”
- fragility fx’s occur in spine, hip, & distal radius
Why more common in women?
- Lower calcium intake
- Less bone mass (b/c generally smaller frame)
- Bone resorption begins earlier & accelerates >menopause
- Pregnancy & breastfeeding
- Longevity (inc likelihood)
Risk Factors
- Advancing age (>50 y.o.)
- Female gender
- Low body weight
- White or Asian ethnicity
- Current cigarette smoking
- Non-traumatic fx
- Sedentary lifestyle
- Postmenopausal (estrogen deficiency)
- Fhx
- Diet low in calcium or vitamin D deficiency
- Excessive use of alcohol (>2-3 drinks/day)
- Low testosterone level in men
Risk Factors cont’d
- Spec dz’s assoc w/ like IBD, intestinal malabsorption, kidney dz, RA, hyperthyroidism, chronic alcoholism, cirrhosis of the liver, hypogonadism, & DM
Many rx’s can interfere w/bone metabolism like
- corticosteroids
- anti-seizure (divalproex sodium [Depakote], phenytoin [Dilantin])
- aluminum-containing antacids
- heparin
- certain cancer treatments
- excessive thyroid hormones
Long-term corticosteroid use is a major contributor to osteoporosis
Preventive Factors
- Regular weight-bearing exercise
- Fluoride
- Calcium
- Vitamin D
- 15 mins of sunshine/day
Etiology & Pathophysiology
- Peak bone mass (by age 20) determined by heredity, nutrition, exercise, & hormone function
- Bone loss >35-40 y.o. inevitable; rate of loss variable
- Rapid bone loss for women @ menopause
- Remodeling
> Osteoblasts - deposit bone
> Osteoclasts - resorb bone
! In osteoporosis, bone resorption exceeds bone deposition
Clinical Manifestations
- Occurs most commonly in spine, hips, & waist
- Back pain
- Spontaneous fx’s
- Gradual loss of height
- Dowager’s hump (kyphosis)
Screening Guidelines
- Initial bone scan in women <65
- Repeat in 5-10 yrs if normal
- Is not suggested to have them more freq than once q2yr
- Earlier & more frequent if high risk
- Men screened <70
> By age 50 if high risk (e.g., low body wt, hypogonadism)
Diagnostic Studies
- BMD measurements obtained through a dual-energy x-ray absorptiometry (DEXA) scan
- Fx risk assessment tool, or FRAX
- Prevention & early screening is the treatment focus
- Often goes unnoticed b/c it cannot be detected by conventional xray until 25-40% of calcium in bone is lost
> Serum calcium, phosphorous, & alk phos levels are normal, although alk phos may be elevated >a fx
- Bone mineral density (BMD) is determined by peak bone mass & amount of bone loss
- Types of BMD measurement incl quantitative ultrasound (QUS) & dual-energy xray absorptiometry (DEXA)
> a DEXA scan gives precise measurements @ clinically relevant skeletal points within the body, which highlight areas for future fx risks
- 1 of the most common BMD studies is DXA, which measures bone density in the spine, hips, & forearm (the most common sites of fx’s resulting from osteoporosis)
- also useful to evaluate changes in bone density over time & to assess the effectiveness of treatment
- QUS measures bone density w/sound waves in the heel, kneecap, or shin
The most widely used tool is the ____, which was developed by the WHO’s Collaborating Centre for Metabolic Bone Disease
Fracture Risk Assessment Tool (FRAX)
A T-score of ____ indicates normal bone density
≥ -1
Osteoporosis is defined as a BMD of ____ below the mean BMD of young adults
≤ -2.5
Osteopenia is defined as bone loss that is more than normal (a T-score between ___ and ___), but not yet at the level for a dx of osteoporosis
-1 & -2.5
Sometimes the HCP will ask for a Z-score instead of a T-score
In this case, a person is compared to someone her own age &/or ethnic group instead of an individual in the best health @ 30 y.o.
A low Z-score that is less than ___ is an indication of a bone density problem
-2.0
Collaborative Care - Focus on
- Proper nutrition
- Calcium supplements
- Exercise
- Prevention of fractures
- Medication therapy
Treat if
- T-score less than -2.5
- T-score between -1 and -2.5 w/addl risk factors
- Prior h/o hip or vertebral fx
Risk assessment - FRAX (takes into acct BMD & addl clinical factors when assessing fx risk)
Calcium is best absorbed over the course of a whole day & not more than 500mg @ a time
Adequate Calcium Intake
____ mg/day premenopausal & postmenopausal taking estrogen
____ mg/day postmenopausal w/o estrogen
Supplemental calcium must be taken in divided doses w/food to enhance absorption
1000
1500
Good sources of calcium
- Milk (whole/skim)
- Yogurt
- Turnip greens
- Cottage cheese
- Ice cream
- Sardines
- Spinach
- Vitamin D necessary for calcium absorption/function; bone formation
- Sunlight for 20 minutes adequate
- Supplemental (800-1000 IU/day)
> Postmenopausal
> Older adults
> Homebound
> Minimal sun exposure
- Weight-bearing exercise
> Build up & maintain bone mass
> Increase strength, coordination, balance
> Walking, hiking, weight training, stair climbing, tennis, dancing - Quit smoking
- Decrease alcohol intake
- Treatment of existing disease
> Prevent further loss w/supplements & meds
> Keep ambulatory
> Gait aid to prevent falls/fx’s
> Brace for vertebral fx
> Vertebroplasty & kyphoplasty to treat osteoporotic vertebral fx
In ____, an air bladder is inserted into the collapsed vertebra & inflated to regain vertebral body height & then bone cement is injected
kyphoplasty
In ___, bone cement is injected into the collapsed vertebra to stabilize it, but it does not correct the deformity
vertebroplasty
Bisphosphonates
- Inhibit bone resorption
- S/e: anorexia, weight loss, gastritis
- Proper admin
> take w/full glass of water
> take 30 min before food or other meds
> remain upright for @ least 30 min
- Precautions have been shown to dec GI s/e (esp esophageal irritation) & inc absorption
- Rare & serious s/e of bisphosphonates is jaw osteonecrosis (bone death)
- Alendronate (Fosamax) - once/wk oral tablet
- Ibandronate (Boniva) & risedronate (Actonel) - once/month oral tablet
- Zoledronic acid (Reclast) - appvd for once/yearly IV infusion & can prevent osteoporosis for 2 yrs >a single infusion
- flu-like sx’s for first few days >admin
?
- inhibits bone resorption
- give IM,SC form at night to minimize s/e (nausea, facial flushing)
- alternate nostrils when using nasal form (no nausea)
- must use calcium supplementation (to prevent 2° hyperparathyroidism)
Calcitonin
Denosumab (Prolia, Xgeva)
- Monoclonal ab for postmeno women
-
SC inj q6mos
> binds to protein RANKL
Management of pts receiving corticosteroids
> prescribe lowest effective dose
> ensure adequate intake of calcium & vitamin D, incl supplementation when osteoporosis rx’s prescribed
* if osteopenia evident on bone densitometry in ppl taking corticosteroids, treatment w/bisphosphonates may be considered
Estrogen agonists/antagonists - raloxifene (Evista)
- Only rx in its class appvd for prevention & treatment of osteoporosis
! Not for women w/ h/o thromboembolism; is hepatotoxic
