Secondary Causes of Osteoporosis

Abstract

A general knowledge of secondary causes of bone loss and osteoporosis is useful and necessary in the practice of densitometry. It must be remembered that the bone density study provides information on the density of the bone at that moment only. It does not, by itself, identify any magnitude of bone loss and certainly cannot be used to identify the cause of any suspected bone loss. It is a single snapshot in time, telling the physician what the bone density is that day, but not how or why it got that way. Because of this, any time that the bone density is classified as low or osteoporotic, an evaluation of the patient for secondary causes of bone loss is appropriate. This evaluation would be performed by the patient’s treating physician, and the extent of the evaluation would be guided by his or her knowledge of the patient. If the patient is well known to the physician, a review of the patient’s medical records may be all that is warranted. It is also possible that additional testing or inquiry may be necessary to exclude causes of bone loss and conditions other than postmenopausal or age-related osteoporosis, as specific interventions may be necessary for successful treatment. Even if the densitometrist is not the treating physician, he or she may still be called upon to render an opinion as to the possible differential diagnoses for suspected bone loss and any appropriate evaluations necessary to exclude those possibilities. The International Society for Clinical Densitometry (ISCD) recommended in 2003 (1) that bone density reports contain a reminder to the referring physician that a “medical evaluation for secondary causes of low BMD may be appropriate.” Specific recommendations regarding the nature of such an evaluation were considered optional. The ability to make specific recommendations, however, is desirable and often necessary in order to assist the referring physician.