Diagnosis of renal osteodystrophy.

The idiom renal osteodystrophy (ROD) represents a heterogeneous pattern of bone disturbances caused by chronic renal insufficiency and concomitant diseases. For the clinical decision of therapy it is most important to differentiate between high and low or adynamic turnover ROD because the therapeutically consequences of these two ends of the ROD spectrum are fundamentally different. Bone histology remains the gold standard for the exact classification of ROD. Serological markers of bone metabolism are not suited for the accurate nomenclature of ROD but are useful for the sequential follow up of ROD after a clear diagnosis has been made. Similarly, radiological diagnosis of ROD using dual energy X-ray absorptiometry (DEXA) or quantitative computer tomography scan (q-CT) is inaccurate and thus more suited for the routine follow up of established disease. Besides mineralization, bone strength and the rate of fractures are strongly determined by the architecture of the bone matrix. This information, however, is also only available on bone biopsy sections and cannot be estimated by non-invasive diagnostic methods. In summary, bone biopsy should be used more liberally for correct classification of bone disease. The sequential follow up and guidance of therapy success can be performed by non-invasive procedures such as biochemical bone marker determination in blood. X-ray imaging and densitometry is suitable only for sequential evaluation of osteoporosis.