Spectrum of renal osteodystrophy in children on continuous ambulatory peritoneal dialysis

Background: The prevalence of different types of bone disease in chronic re nal failure (CRF) has changed significantly during the last decade. The aim of the present study is to evaluate the spectrum of bone disease in childr en with CRF undergoing continuous ambulatory peritoneal dialysis (CAPD). Methods: Seventeen children with CRF on CAPD aged 7-20 years were evaluated . All patients had received regular vitamin D and calcium carbonate therapy during the 6 months preceding the bone biopsy. Serum calcium, phosphate, a lkaline phosphatase and immunoreactive parathyroid hormone (iPTH) levels we re measured and hand X-rays were performed, Transiliac bone biopsies were a nalyzed for histologic diagnosis. Results: High turnover renal osteodystrophy (ROD) was the most common bone disease, present in eight patients (47%). Five patients (29%) had low turno ver bone disease, and four (24%) had mixed ROD. The mean age of the high tu rnover ROD group was higher than that of the low turnover group (14 +/- 3 v s. 11 +/- 3 years, P < 0.05). even of the nine patients who had tubulo-inte rstitial nephritis were found to have high turnover bone disease. In contra st, none of the patients with glomerulonephritis exhibited high turnover bo ne lesions. Mean serum calcium levels were found to be significantly higher in the low turnover group compared with the patients with high turnover bo ne disease (P < 0.001). A serum iPTH level > 200 pg/mL was 100% sensitive a nd 66% specific in identifying patients with high turnover ROD. Conclusion: The spectrum of bone disease of the children with CRF undergoin g CAPD seems to depend on the rate of CRF and primary disease. The risk of developing overt hyperparathyroid bone disease is high in children with slo wly progressing forms of renal pathology and especially in those with tubul o-interstitial disease. In contrast, children with glomerular diseases who had a more rapidly progressive course may have a lesser risk of developing high turnover bone disease. The results of the present study indicate that even routinely prescribed regular vitamin D therapy early in the course of disease may lead to low turnover bone lesion in small children who have CRF due to rapidly progressive forms of renal pathology.