| History: A thorough history focusing on known risk factors for osteoporosis is essential and should include underlying medical conditions, medication use (past and current), family history of osteoporosis, maternal history of fractures, reproductive history in women (age of menarche and menopause, contraceptive use, estrogen replacement therapy), diet (especially calcium and vitamin D intake), alcohol and tobacco use, and physical activity level.
Osteoporosis is often not diagnosed until a fracture occurs, although it may be an incidental finding during evaluation for another problem. Fractures may occur after a fall, sudden movement, lifting, jumping, or even minor events such as bumping the rib cage, coughing, or vigorous walking. Individuals may complain of pain in the area of the fracture, a change in body height if the spine is involved, weakness, and stiffness. Physical exam: If osteoporosis is suspected, the individual should undergo a completed medical examination. Height and body weight are used to calculate the body mass index (BMI). There may be an overall loss of height or change in the ratio of upper body to lower body height. If the vertebrae are involved, there may be midline back pain with an increase in the thoracic curve (kyphosis). Exaggerated upper spine curve or thoracic kyphosis is called "dowager's hump." If there is an acute fracture of the hip or wrist, deformity, pain, tenderness over the fracture, loss of motion, and swelling may be obvious. Tests: Laboratory tests are done to rule or confirm out other diagnoses and underlying disease processes, as well as to evaluate nutritional status. These tests usually include a complete blood count (CBC), electrolyte levels, calcium, phosphate, and liver function tests. Most blood tests (serum chemistries) involving calcium, as well as bone function studies, are normal in primary osteoporosis. Other more specialized tests may be indicated in the evaluation of secondary osteoporosis or if high bone turnover is suspected. Biochemical markers of bone turnover, measured using blood tests, reflect bone formation or resorption. These tests can be performed before and during treatment to help monitor treatment response but are not helpful in initial diagnosis. In rare cases, where a blood (hematologic) disorder is suspected, a bone marrow biopsy may be ordered.
Plain x-rays may appear normal in early osteoporosis, since 30% to 80% of the bone mineral must be lost before changes are obvious on x-ray (Jacobs-Kosmin). X-rays are used to evaluate possible fractures rather than to diagnose primary or secondary osteoporosis.
A special radiographic study, dual-energy x-ray absorptiometry (DEXA), is used to screen individuals at risk for osteoporosis, confirm the diagnosis of osteoporosis, and follow changes in bone mass over time. DEXA measures the density of the spine, hip, wrist, and total skeleton. DEXA is the most specific radiographic study for osteoporosis and is the best for predicting fracture risk. It uses a relatively low dose of radiation and is quick and non-invasive. Other radiographic methods for assessment of osteoporosis in special situations include quantitative CT scanning, which measures bone density of the spine but results in higher radiation exposure than DEXA; peripheral DEXA, which measures bone density at the wrist and is useful in screening and identifying individuals who are at very low risk for fracture; single-photon absorptiometry; dual-photon absorptiometry; and radiographic absorptiometry. Quantitative ultrasound is a low-cost portable screening method with no radiation exposure, but it lacks the accuracy and precision of other methods. |