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Received: February 2, 2001
Accepted: May 1, 2001
Key Words
Osteoporosis, differential diagnosis * Dual x-ray absorptiometry * Low bone density * Vitamin D deficiency * Hypercalciuria * Primary hyperparathyroidism
Abstract
Background: Dual x-ray absorptiometry (DEXA) is widely used to identify persons at increased risk for osteoporotic fractures. It does not, per se, give us any diagnostic information that is necessary to determine the best therapeutic approach in an individual case. Objective: Identify conditions and tests that may impact on the diagnosis and the treatment of subjects with low bone densitometry scores. Subjects and Methods:We evaluated clinically, by history, physical examination and laboratory tests, 272 persons with low spinal and/or femoral bone absorptiometry for potential causes of osteoporosis. Results: We found that 25.3% of the patients had significant underlying conditions: 17.9% had subclinical vitamin D deficiency (osteomalacia), 6.7% had hypercalciuria and 0.7% had primary hyperparathyroidism. Conclusion: It is mandatory to go through a differential diagnosis in every case with absorptiometric data compatible with the diagnosis of osteoporosis. At the minimum, blood calcium
and 25-hydroxyvitamin D and 24-hour urinary calcium excretion should be examined. This will allow the physician to determine the appropriate course of therapy in any individual patient who has abnormal DEXA findings.
Copyright (C) 2002 S. Karger AG, Basel
Osteoporosis is a condition in which bone tissue is quantitatively reduced to such a degree that fractures occur with little or no trauma. There is no specific marker in the blood, or in the urine, that establishes the diagnosis. Furthermore, there are a number of medical conditions which may result in the development of osteoporosis, and some of those may be occult, especially in the elderly population in whom osteoporosis is usually found.
The introduction of dual photon absorptiometry (DPA), and, more recently, of dual energy x-ray absorptiometry (DEXA), made possible the measurement of bone density with accuracy and sensitivity heretofore not available to us (absorptiometry calculates the mass in a cross-sectional area of the bone (i.e. Gm/cm^sup 2^) rather than mass per unit volume (e.g. Gm/cm^sup 3^)). We now can quantify the amount of bone in heel, wrist, spine or hip, or even the entire body. Among its other uses, this technique can identify patients, and anatomical...