[The diagnosis of metabolic bone diseases]

Physical semeiotics, the laboratory, radiology and histology represent the diagnostic tools for metabolic bone diseases. Past medical history and a full objective examination form the basis for every type of diagnostic and therapeutic approach. Familial patterns, the range of drugs used by the patient, the concomitance of diseases affecting mineral metabolism, and the presence of deformities or typical characteristics of some clinical conditions allow the clinician to orientate his diagnosis. Some laboratory tests (serum calcium and phosphate, calciuria) are useful for screening, whereas others (parathyroid hormone and other calciotrophic hormones, biochemical parameters of bone remodeling) must be carried out only for precise diagnostic purposes. In addition to highlighting and characterizing fractures, plane radiology is indicated for the differential diagnosis of focal bone diseases. In the latter diagnosis is facilitated by bone scintigraphy which reveals areas of accelerated bone remodelling. The quantitative evaluation of bone mass using non-invasive methods is of fundamental importance in osteopenic syndromes. Of all the techniques evolved in the past, only quantitative computerized tomography and X-ray computerized mineralometry are used today in the diagnosis and management of osteoporotic patients. The choice of one or other technique should be based on the clinical necessity and on their respective accuracy and reproducibility. Histomorphometric bone biopsy is indicated only in cases of rapid bone loss with uncertain biochemical conditions and for the diagnosis of mineralization disorders.