Ch 63 Osteoporosis
Osteoporosis •Chronic, progressive metabolic bone disease marked by -Low bone mass -Deterioration of bone tissue •Leads to increased bone fragility
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Osteoporosis •Screening guidelines -Initial bone density test in women over age 65 •Repeat in 15 years if normal •Earlier and more frequent if high risk -Currently no evidence of benefit for screening in men
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Drug Therapy •Calcitonin -Inhibits bone resorption -Give IM form at night to minimize side effects -Alternate nostrils when using nasal form -Calcium supplementation is needed
Calcitonin is secreted by the thyroid gland and inhibits osteoclastic bone resorption by directly interacting with active osteoclasts. Salmon calcitonin (Calcimar) is available in intramuscular, subcutaneous, and intranasal forms. Administration of the intramuscular or subcutaneous form of the drug at night has been shown to decrease associated side effects of nausea and facial flushing associated with this drug. Nausea does not occur with the nasal spray. If patients are using the nasal form, teach them to alternate nostrils daily. Nasal dryness and irritation are the most frequent side effects. Calcium supplementation is needed to prevent secondary hyperparathyroidism.
Etiology and Pathophysiology •Preventive factors -Regular weight-bearing exercise -Fluoride -Calcium -Vitamin D
Decreased risk is associated with regular weight-bearing exercise and fluoride, calcium, and vitamin D ingestion.
Osteoporosis •Why more common in women? -Lower calcium intake -Less bone mass -Bone resorption begins earlier and becomes more rapid at menopause -Pregnancy and breastfeeding -Longevity
Osteoporosis is more common in women than in men for several reasons: Women tend to have lower calcium intake than men throughout their lives (men between 15 and 50 years of age consume twice as much calcium as women). Women have less bone mass because of their generally smaller frame. Bone resorption begins at an earlier age in women and becomes more rapid at menopause. Pregnancy and breastfeeding deplete a woman's skeletal reserve unless calcium intake is adequate. Longevity increases the likelihood of osteoporosis.
Osteoporosis •Over 54 million people in the United States •One in 2 women and 1 in 4 men over 50 will sustain an osteoporosis-related fracture •Known as the "silent thief"
Over 54 million persons in the United States have decreased bone density or osteoporosis. One in two women and one in four men over age 50 will sustain an osteoporosis-related fracture during their lifetime. Osteoporosis is known as the "silent thief" because it slowly robs the skeleton of its banked resources. Bones eventually become so fragile that they cannot withstand normal mechanical stress.
Clinical Manifestations •Occurs most commonly in spine, hips, and wrists •Back pain •Spontaneous fractures •Gradual loss of height •Kyphosis or "dowager's hump "
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Diagnostic Studies •History and physical exam •X-ray and lab studies not diagnostic •Bone mineral density (BMD) -Quantitative ultrasound (QUS) -Dual-energy x-ray absorptiometry (DXA)
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Etiology and Pathophysiology •Peak bone mass (by age 20) determined by heredity, nutrition, exercise, and hormone function •Bone loss after age 35-40 inevitable, rate of loss variable •Rapid bone loss for women at menopause
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Etiology and Pathophysiology •Remodeling -Osteoblasts - deposit bone -Osteoclasts - resorb bone •In osteoporosis, bone resorption exceeds bone deposition
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Etiology and Pathophysiology •Risk factors -Advancing age (>65 yr) -Female gender -Low body weight -White or Asian -Current cigarette smoking -Prior fracture -Sedentary lifestyle
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Etiology and Pathophysiology •Risk factors -Estrogen deficiency -Family history -Diet low in calcium/vitamin D deficiency -Excessive use of alcohol (>2 drinks/day) -Low testosterone in men -Specific diseases -Certain drugs
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Interprofessional Care •Adequate calcium intake -1000 mg/day for •women ages 19-50 years •Men ages 19-70 years -1200 mg/day for •Women 51 years or older •Men 71 years or older
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Interprofessional Care •Focus on -Proper nutrition -Calcium supplements -Exercise -Prevention of fractures -Drug therapy
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Interprofessional Care •Good sources of calcium -Milk -Yogurt -Turnip greens -Cottage cheese -Ice cream -Sardines -Spinach
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Interprofessional Care •Supplemental calcium -Take in divided doses -Calcium carbonate •40% elemental calcium •Take with meals -Calcium citrate •20% elemental calcium •Less dependent on stomach acid
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Interprofessional Care •Treat if -T-score less than -2.5 -T-score between -1 and -2.5 with additional risk factors -Prior history of hip or vertebral fracture •Risk assessment -www.shef.ac.uk/FRAX
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Interprofessional Care •Vitamin D necessary for calcium absorption/function; bone formation •Sunlight for 20 minutes adequate •Supplemental (800-1000 IU/day) -Postmenopausal -Older adults -Homebound/long-term care -Minimal sun exposure
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Normal vs. Osteoporotic Bone
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Audience Response Question Alendronate (Fosamax) is prescribed for a patient with osteoporosis. The nurse teaches the patient that a.the drug must be taken with food to prevent GI side effects. b.bisphosphonates prevent calcium from being taken from the bones. c.lying down after taking the drug prevents light-headedness and dizziness. d.taking the drug with milk enhances the absorption of calcium from the bowel.
Answer: B Rationale: Alendronate is a bisphosphonate that prevents calcium from being taken from the bones by inhibiting osteoclast-mediated bone resorption. Bisphosphonates should be taken with a full glass of water, 30 minutes before food or other medications, and the patient should remain upright for at least 30 minutes after administration. These precautions aid in drug absorption and decrease gastrointestinal side effects (especially esophageal irritation).
Audience Response Question Which patient would be at greatest risk for developing osteoporosis? A 73-year-old man who has five alcoholic drinks per week and limits sun exposure to prevent recurrence of skin cancer. b.An 84-year-old man who has recently been diagnosed with hypothyroidism and is prescribed levothyroxine (Synthroid). c.A 69-year-old woman who had a renal transplant 5 years ago and has been taking prednisone to prevent organ rejection. d.A 55-year-old woman who recently had a hysterectomy with bilateral salpingo-oophorectomy and refuses estrogen therapy.
Answer: C Rationale: Risk factors for osteoporosis include advanced age (>65 years), female gender, low body weight, white or Asian ethnicity, current cigarette smoking, nontraumatic fracture, inactive lifestyle, family history of osteoporosis, diet low in calcium or vitamin D deficiency, excessive use of alcohol (>2 drinks per day), postmenopausal, including premature or surgical menopause, and long-term use of corticosteroids, thyroid replacements, heparin, long-acting sedatives, or antiseizure medications. Long-term corticosteroid (such as prednisone) use is a major contributor to osteoporosis. The other patients have risk factors for osteoporosis, but the 69-year-old female is at highest risk.
Drug Therapy •Bisphosphonates -Inhibit bone resorption -Side effects: anorexia, weight loss, gastritis -Proper administration •Take with full glass of water •Take 30 minutes before food or other meds •Remain upright for at least 30 minutes
Bisphosphonates inhibit osteoclast-mediated bone resorption and slow the cycle of bone remodeling. Although a modest increase in BMD is typical, bone remodeling may be suppressed to the extent that normal bone formation is impaired and fracture risk increases. These drugs are widely used in the prevention and treatment of osteoporosis. Common side effects are anorexia, weight loss, and gastritis.
Drug Therapy •Denosumab (Prolia) -Monoclonal antibody for postmenopausal women -Subcutaneous injection every 6 months •Management of patients receiving corticosteroids
Denosumab (Prolia) may be used for postmenopausal women with osteoporosis who are at high risk for fractures. It is a monoclonal antibody that binds to a protein (RANKL) involved in the formation and function of osteoclasts. Denosumab is given by a health care professional as a subcutaneous injection every 6 months. Medical management of patients receiving corticosteroids includes prescribing the lowest effective dose and ensuring an adequate intake of calcium and vitamin D, including supplementation when osteoporosis drugs are prescribed. If osteopenia is evident on bone densitometry in people who are taking corticosteroids, treatment with bisphosphonates may be considered
Drug Therapy •Selective estrogen receptor modulators -Raloxifene (Evista) -Reduces bone resorption •Teriparatide (Forteo) -Portion of parathyroid hormone -First drug to stimulate new bone formation
Raloxifene (Evista) is a selective estrogen receptor modulator (SERM). This drug mimics the effect of estrogen on bone by reducing bone resorption without stimulating the tissues of the breast or uterus. Raloxifene in postmenopausal women significantly increases BMD. Side effects include leg cramps, hot flashes, and blood clots. Raloxifene may decrease breast cancer risk. Similar to tamoxifen, it blocks the estrogen receptor sites of cancer cells. Teriparatide (Forteo) is a recombinant form of human parathyroid hormone (PTH) that increases the action of osteoblasts. This drug is used to treat osteoporosis in men and postmenopausal women at high risk for fractures, including risk related to long-term corticosteroid use. Side effects can include leg cramps and dizziness. Teriparatide is the first drug approved for the treatment of osteoporosis that stimulates new bone formation in osteoporosis; most drugs only prevent further bone loss. It is administered daily by subcutaneous injection from a preloaded pen.
Diagnostic Studies •T-scores -T-score between +1 and -1 = normal bone density -T-score between -1 and -2.5 = osteopenia -T-score -2.5 or lower = osteoporosis •Z-score compares with someone own age and ethnicity
The BMD test results are compared to the ideal or peak bone mineral density of a healthy 30-year-old adult, and reported as T-scores. A T-score of 0 means the BMD is equal to the norm for a healthy young adult. Differences between the BMD and that of the healthy young adult norm are measured in units called standard deviations (SDs). The more standard deviations below 0 (indicated as negative numbers), the lower the BMD and the higher the risk of fracture. A T-score between +1 and −1 is considered normal. A T-score between −1 and −2.5 indicates osteopenia (bone loss that is more than normal, but not yet at the level for a diagnosis of osteoporosis). A T-score of −2.5 or lower indicates osteoporosis. The greater the negative number, the more severe the osteoporosis With a Z-score, a person is compared with someone his or her own age, gender, and/or ethnic group instead of a healthy 30-year-old. Among older adults, Z-scores can be misleading because decreased bone density is common. If the Z-score is -2 or lower, it may suggest that something other than aging is causing abnormal bone loss.
