Source: O’Connell, MB,
Vondracek SF. Osteoporosis and Other Metabolic Bone Diseases. In:
DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach.
8th ed. http://accesspharmacy.com/content.aspx?aid=7996689.
Accessed June 23, 2012.
- Bone disorder characterized by low bone mineral density
(BMD), impaired bone architecture, and compromised bone strength
predisposing to increased fracture risk.
- Primary: no known cause
- Secondary: caused by drugs or other diseases
- Men and women begin to lose bone mass starting in third
or fourth decade because of reduced bone formation.
- Estrogen deficiency during menopause increases osteoclast
activity, increasing bone resorption more than formation.
- Etiology of male osteoporosis involves secondary causes and
- Age-related osteoporosis occurs because of hormone, calcium,
and vitamin D deficiencies leading to accelerated bone turnover
and reduced osteoblast formation.
- Drug-induced osteoporosis may result from:
- Thyroid hormone
- Antiepileptic drugs (e.g., phenytoin, phenobarbital)
- Depot medroxyprogesterone acetate
- Other drugs
- Affects over 10 million Americans, and more than 34 million
Americans have low bone mass.
- Responsible for 1.5 million fractures in United States annually.
- Postmenopausal White women have 50% lifetime chance
of developing osteoporosis-related fracture, whereas men have 20% lifetime
- Measurement of BMD at peripheral sites (forearm, heel,
and phalanges) with ultrasound or dual-energy x-ray absorptiometry
(DXA) scan used for screening and to determine need for further testing.
- Low BMD
- Female sex
- Advanced age
- History of previous low trauma (fragility) fracture
- Osteoporotic fracture in first-degree relative
- Low body weight or body mass index
- Premature menopause (before age 45)
- Secondary osteoporosis (especially rheumatoid arthritis)
- Past or present systemic oral glucocorticoid therapy
- Current cigarette smoking
- Alcohol intake of 3 or more drinks per day
- Low calcium intake
- Low physical activity
- Minimal sun exposure
- Fragility fracture may be first sign of osteoporosis;
fractures can occur after bending, lifting, falling, or independent
of any activity.
- Most common fracture sites are vertebrae, proximal femur,
and distal radius (wrist or Colles fracture).
- Two thirds of patients with vertebral fractures asymptomatic;
the remainder present with back pain that radiates down leg after
new vertebral fracture.
- Pain usually subsides after 2–4 weeks, but chronic
residual low back pain may persist.
- Patients with nonvertebral fractures frequently present with
pain, swelling, and reduced function and mobility at fracture site.
- Physical examination findings include postural changes (kyphosis)
and loss of height (more than 1.5 in [3.8 cm]).
Means of Confirmation
- Presence of low-trauma fracture, or
- Central hip or spine DXA scan using World Health Organization
(WHO) T-score thresholds
- Complete blood count (CBC), creatinine, blood urea nitrogen,
calcium, phosphorus, alkaline phosphatase, albumin, thyroid-stimulating
hormone, free testosterone, 25-hydroxyvitamin D, and 24-hour urine
concentrations of calcium and phosphorus.
- Urine or serum biomarkers (osteocalcin and cross-linked N-telopeptides
of type I collagen) sometimes used.
- Radiographs of spine and pelvis may show demineralization
and compressed vertebrae.