Osteoporosis-causas, síntomas, diagnóstico, tratamiento y atención continua

Basics

Description

A skeletal disease characterized by low bone mass, disruption of skeletal microarchitecture, and increased skeletal fragility resulting in fractures occurring with a fall from standing height or less or with no trauma

Epidemiology

Predominant age: Elderly >60 years of agePredominant sex: Female > Male (80%/20%)

Incidence

9 million osteoporotic fractures worldwide in 2000

Prevalence

10 million Americans have osteoporosis.24% of women >50 years of age7.5% of men >50 years of age

Risk Factors

Nonmodifiable: Advanced age (>65 years)Female genderCaucasian or AsianFamily history of osteoporosisHistory of atraumatic fractureModifiable: Low body weight (<58 kg or body mass index <20)Calcium or vitamin D deficiencyInadequate physical activityCigarette smokingExcessive alcohol intake (>2 drinks/d)Medications: Chronic corticosteroids, excessive thyroid hormone replacement, medroxyprogesterone acetate, heparin

Genetics

Familial predispositionMore common in Caucasians and Asians than in African Americans and Hispanics

General Prevention

The aim in the prevention and treatment of osteoporosis is to prevent fracture.

Exercise (weight-bearing, aerobic, and strength training) increases bone mineral density (BMD), although unclear if it prevents fractures (1)[B].Calcium (1,200 mg) and vitamin D (800 IU) dailyAvoid smoking.Limit alcohol use (<2 drinks/d).Screen all women =65 years of age and women =60 years of age who are at high risk for fracture (2)[B].Consider screening elderly men at high risk for fracture (3)[C].Correct treatable medical conditions and other risk factors.

Pathophysiology

Imbalance between bone resorption and bone formationTrabecular bone (vertebral) more active than cortical (hip) bone

Etiology

Commonly Associated Conditions

Malabsorption syndromes: Gastrectomy, inflammatory bowel disease, celiac diseaseHypoestrogenism: Menopause, hypogonadism, eating disorders, elite athletesChronic liver disease, hemochromatosisEndocrinopathies: Hyperparathyroidism, hyperthyroidismMultiple myeloma, multiple sclerosis, osteomalacia, rheumatoid arthritisMedications (see “Medications” under “Risk Factors”)

 

Diagnosis

History

Review risk factors.Online risk factor assessment tools are available, although external validation is lacking [e.g., FRAX (http://www.sheffield.ac.uk/FRAX/index.htm), Garvan (http://garvan.org.au/promotions/bone-fracture-risk/calculator/).Often no clinic findings until fracture occurs

Physical Exam

Thoracic kyphosisHeight loss >1.5 cm

Diagnostic Tests & Interpretation

Dual-energy x-ray absorptiometry (DEXA) of the lumbar spine/hip is the “gold standard” for diagnosis of osteoporosis (see “Initial Approach” under “Imaging”).

Lab

Initial lab tests

To elicit common causes of secondary osteoporosis:

25-hydroxyvitamin DComplete blood countSerum calcium, total protein, creatinine, alkaline phosphatase

Follow-Up & Special Considerations

Consider further lab work depending on initial evaluation, Z-score < -2.0, or young age.

Parathyroid hormone (PTH), ionized calcium (hyperparathyroidism)Thyroid-stimulating hormone (hyperthyroidism)Testosterone (hypogonadism in men)Serum protein electrophoresis (multiple myeloma)Urinary free cortisol (Cushing disease)Vitamin B12 level and intrinsic-factor antibody (pernicious anemia)IgA antiendomysial antibodies (celiac sprue)Serum and 24-h urine calcium, serum phosphate (osteomalacia)Markers of bone resorption (urine N-telopeptides of type 1 collagen, serum C-telopeptides of type 1 collagen, serum N-terminal propeptide of type 1 procollagen): No prospective studies supporting use in osteoporosis diagnosis and management; potential role for identifying patients at high risk for fracture and monitoring response to therapy

Imaging

Initial approach

DEXA of the lumbar spine/hip is the “gold standard” for measuring BMD.BMD is expressed in terms of T-scores and Z-scores. T-score is the number of standard deviations (SDs) a patient's BMD deviates from the mean for young normal (age 25–40 years) control individuals of the same sex.The World Health Organization (WHO) defines normal BMD as a T-score =-1, osteopenia as a T-score between -1 and -2.5, and osteoporosis as a T-score =-2.5.WHO thresholds can be used for postmenopausal women and men >50 years of age.Z-score is a comparison of the patient's BMD with an age-matched population.Z-score <-2.0 should prompt evaluation for causes of secondary osteoporosis.Ultrasound densitometry is used to measure BMD at the calcaneus (heel). It is lower in cost and involves no radiation exposure but is not as accurate as DEXA, and no studies support its use in determining therapy.Plain radiographs lack sensitivity to diagnose osteoporosis, but an abnormality (e.g., widened intervertebral spaces, rib fractures, vertebral compression fractures, etc.) should prompt evaluation of BMD.

Diagnostic Procedures/Surgery

Bone biopsy rarely is needed to rule out neoplasms and other metabolic bone diseases.

Pathological Findings

Reduced skeletal mass, trabecular bone thinned or lost more so than cortical boneOsteoclast and osteoblast number variableNo evidence of other metabolic bone diseases and no increase in unmineralized osteoidMarrow normal or atrophic

Differential Diagnosis

Multiple myeloma or other neoplasmsOsteomalaciaType I collagen mutationsOsteogenesis imperfecta

Treatment

Treat patients with a T-score =-2.5 with no risk factors, patients with a T-score =-2.0 and 1 or more risk factors, and patients with a prior history of osteoporotic fracture at the spine or hip.

Medication

Calcium 1,500 mg and vitamin D 800 IU (minimally) per day

First Line

Bisphosphonates: Alendronate 10 mg PO daily or 70 mg PO weeklyRisedronate 5 mg PO daily, 35 mg PO weekly, 75 mg PO twice monthly, or 150 mg PO monthlyZoledronic acid 5 mg IV yearlyThese drugs become incorporated into skeletal tissue, where they inhibit the resorption of bone by osteoclasts.Number needed to treat (NNT) to prevent vertebral fracture = 17.NNT to prevent hip fracture = 100 (4)[A].Ibandronate increases bone density but does not appear to decrease fractures.

Second Line

Raloxifene 60 mg PO daily: Selective estrogen receptor modulator with positive effects on BMD and fracture risk but no stimulatory action on breasts or uterusNNT with 60 mg/d for 3 years to prevent 1 postmenopausal woman with osteoporosis from developing a vertebral fracture = 29.Decreases vertebral but not hip fractures (5)[A]; increases risk of thromboembolismTeriparatide 20 mg SC daily: Recombinant formulation of PTH; when given daily, it promotes new bone formation.Studies have shown a reduction in the incidence of vertebral fractures by 65% (6)[B].No data exist on its safety and efficacy after >2 years of use.Primarily indicated for those with worsening osteoporosis despite bisphosphonate therapy.Estrogen 0.625 mg PO daily (with progesterone if women has a uterus): Effective in prevention and treatment of osteoporosis (35% reduction in hip and vertebral fractures after 5 years of use), but the risks (e.g., increased rates of myocardial infarction, stroke, breast cancer, pulmonary embolus, and deep vein thrombosis) must be weighed against the benefits (7)[B].Strontium 2 g PO daily: Appears to inhibit bone resorption and increase bone formationAvailable for use in EuropeNNT to prevent vertebral fracture = 13.NNT to prevent hip fracture = 50 (8)[B].Denosumab: Human monoclonal antibody RANKL receptorInhibits Osteoclast formationNNT to prevent vertebral fracture = 20 after 3 yearsNNT to prevent hip fracture = 200 after 3 years (9)Calcitonin: Acts by reducing the number of osteoclasts, therefore decreasing bone turnoverHas been shown to increase BMD, but no studies have shown conclusively a reduction in the occurrence of fractures.May decrease acute vertebral compression-fracture pain (analgesic).

Additional Treatment

Exercise: Any weight-bearing exercise 30 min 3×/wk (1)[B]Smoking cessationDecrease fall risk.Evaluate and treat all patients presenting with fracture resulting from minimal trauma.

Issues for Referral

Endocrinology for recurrent bone loss/fracture despite treatment of osteoporosis and evaluation and treatment of possible secondary causes

Additional Therapies

Physical therapy to help with muscle strengthening to decrease fall risk

Complementary and Alternative Medicine

Isoflavones not better than placebo for bone density and fracture risk

Surgery/Other Procedures

Options for patients with painful vertebral compression fractures failing medical treatment:

Vertebroplasty: Orthopedic cement is injected into compressed vertebral body.Kyphoplasty: A balloon is expanded within compressed vertebral body to reconstruct volume of vertebrae. Cement is injected into the space.

In-Patient Considerations

Initial Stabilization

Usually outpatient careInpatient care for pain control of acute back pain secondary to new vertebral fractures and for acute treatment of femoral and pelvic fractures

Discharge Criteria

Pain controlledFracture stabilizedRehabilitation, nursing home, or home care may be needed following peripheral fractures.

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Weight-bearing exercises such as walking, jogging, stair climbing, and tai-chi. These activities have been shown to decrease falls.All successful studies on the treatment of osteoporosis involve weight-bearing exercise.BMD should be tested no earlier than 2 years after starting bisphosphonate. It is uncertain whether repeat DEXA scanning is of value.Radiographs for acute pain, suspected fractures

Diet

Diet to maintain normal body weightCalcium 1,500 mg and vitamin D 800 IU daily

Patient Education

National Osteoporosis Foundation: WWW.nof.org

Prognosis

With treatment, 80% of patients stabilize skeletal manifestations, increase bone mass, increase mobility, and have reduced pain.15% of vertebral and 20–40% of hip fractures may lead to chronic care and/or premature death.

Complications

Severe, disabling painDorsal/lumbar neurologic deficits secondary to vertebral fracture (rare)

References

1. Bonaiuti D, Shea B, Iovine R, et al. Exercise for preventing and treating osteoporosis in postmenopausal women. Cochrane Database Syst Rev. 2002;CD000333.

2. Screening for Osteoporosis in Postmenopausal Women, Topic Page. September 2002. U.S. Preventive Services Task Force. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/uspstf/uspsoste.htm.

3. Qaseem A, Snow V, Shekelle P, et al. Screening for osteoporosis in men: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2008;148:680–4.

4. Wells GA, Cranney A, Peterson J, et al. Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women. Cochrane Database of Systematic Reviews. 2008, Issue 1. 10.1002/14651858.CD001155.pub2.

5. Ettinger B, Black DM, Mitlak BH, et al. Reduction of vertebral fracture risk in postmenopausal women with osteoporosis treated with raloxifene: results from a 3-year randomized clinical trial. Multiple Outcomes of Raloxifene Evaluation (MORE) Investigators. JAMA. 1999;282:637–45.

6. Neer RM, Arnaud CD, Zanchetta JR, et al. Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis. N Engl J Med. 2001;344:1434–41.

7. Cauley JA, Robbins J, Chen Z, et al. Effects of estrogen plus progestin on risk of fracture and bone mineral density: the Women’s Health Initiative randomized trial. JAMA. 2003;290:1729–38.

8. O’Donnell S, Cranney A, Wells GA, et al. Strontium ranelate for preventing and treating postmenopausal osteoporosis. Cochrane Database Sys Rev. 2006, Issue 4.

9. Cummings SR, San Martin J, McClung MR, et al. Denosumab for prevention of fractures in postmenopausal women with osteoporosis. N Engl J Med. 2009;361:756–65.

Codes

ICD9

733.00 Osteoporosis, unspecified733.01 Senile osteoporosis733.02 Idiopathic osteoporosis733.03 Disuse osteoporosis733.09 Other osteoporosis

Snomed

64859006 osteoporosis (disorder)18040001 senile osteoporosis (disorder)3345002 idiopathic osteoporosis (disorder)53174001 disuse osteoporosis (disorder)

Clinical Pearls

Screen all women and men for risks of osteoporosis.Screen both men and women >60 years of age at increased risk for osteoporosis and candidates for treatment with DEXA scan.Premenopausal women with osteoporosis should be screened for secondary causes of osteoporosis, such as malabsorption syndromes (e.g., celiac sprue), hyperparathyroidism, hyperthyroidism, and medications (e.g., chronic steroid use, etc.).Evaluate and treat all patients presenting with fractures from minimal trauma.If patient is not responding to treatment, consider screening for secondary, treatable cause of osteoporosis.