Imaging of bone in the diagnostics of renal osteodystrophy in children with chronic renal failure.

BACKGROUND

In the last two decades considerable advances have been made in the development of imaging tests of the skeletal system. This progress in diagnostic techniques, along with the growing availability of the tests, renders it necessary to review and evaluate their suitability for daily clinical practice. The aim of this article is to compare the results of radiological testing of bone with densitometrical, histomorphometric, and biochemical tests in children with chronic renal failure.

METHODS

The research involved 31 children with renal failure, of whom 10 were being treated conservatively, 17 by continuous ambulatory peritoneal dialysis (CADO), and 4 by hemodialysis (HD). In all these children, radiological examinations of bone were performed in the arms, knees, and hips, along with tests for the serum concentration of parathormone (iPTH), calcium (Ca), and phosphates (P), and for the activity of alkaline phosphatase (AP). Bone density tests by the DXA method and bone biopsies were also performed. On the basis of radiological evaluation, the patients were divided into two groups: Group I, consisting of 14 children with a normal bone structure image, and Group II, consisting of 17 children with bone atrophy.

RESULTS

No statistically significant differences were discovered in the mean values of the tested biochemical parameters between the two groups. The mineral density of total body was normal in 9 of the 14 patients in Group I (64%), and in 7 of 17 (41%) from Group II. The mineral density of total lumbar spine gave similar results. Lower bone density results were obtained in Group II than in Group I, though only in the case of the lumbar spine were the differences statistically significant. In Group I, 5 cases were discovered of chronic osteodystrophy without osteomalacia and hyperparathyroidism (NB), 2 cases of adynamic bone disease (ABD), 4 cases of hyperparathyroidism (HP), 2 cases of moderate hyperparathyroidism (MHP), and one mixed form (Mix); in Group II, there were 6 NBs, 2 ABDs, 1 case of osteomalacia (OM), 5 HPs, and 3 mixed. Radiological examinations revealed one male in Group I with features of prior Perthes's disease, one with fibrous cortical defect, and four cases of valgity of the coxa valga. In Group II, there were 3 children with radiological changes typical for osteomalacia, and in 1 case typical radiological signs of hyperparathyroidism.

CONCLUSIONS

Given the lack of consistency in the results of the tests here presented, an entire panel of available tests should be performed for the comprehensive evaluation of the status of the skeleton.