Bone diseae in pediatric patients undergoing dialysis with CAPD or CCPD

Abstract

The histologic features of renal osteodystrophy and the prevalence of bone aluminum deposition in children receiving regular dialysis have not been described. Forty-four pediatric patients undergoing continuous ambulatory (CAPD) or cycling (CCPD) peritoneal dialysis had bone biopsies and deferoxamine (DFO) infusion tests; all were receiving oral calcitrol. Osteitis fibrosa (OF) was found in 39%, mild lesions (M) in 25%, normal histology (NH) in 16%, aplastic lesions (AP) in 11%, and osteomalacia (OM) in 9%. Bone surface aluminum (SA) was present by histochemical staining in 10 out of 20 given aluminum-containing phosphate-binding agents and in 0 of 24 treated with calcium carbonate; χ2 = 15.5, P < 0.0001. Serum biochemistries and DFO infusion tests failed to predict bone histology, but plasma aluminum levels were markedly elevated and bone aluminum content was highest in patients with OM. Bone formation rate (BFR) correlated with serum parathyroid hormone (PTH), r = 0.55, P < 0.001; BFR was inversely related to bone aluminum content (r = -0.42, P < 0.01), even in patients with OF (r = -0.66, P < 0.05). All patients with SA > 30% had normal or reduced BFR when compared to those with SA < 30%; χ2 = 12.2, P < 0.005. Based on SA > 30%, six patients were classified as aluminum-related bone disease: three OM, one AP, and two NH. Two-thirds of pediatric patients undergoing CAPD/CCPD have persistent hyperparathyroidism despite treatment with calcitrol, but aluminum can adversely affect BFR when SA exceeds 30% regardless of histologic lesion or serum PTH level.