Mobilization of lead from bone in end-stage renal failure patients with secondary hyperparathyroidism

Background. It is now recognized that long-term exposure to even low levels of lead may increase bone lead content. Lead can then be released in toxic ologically significant amounts during critical states of increased bone tur nover. Methods. Two patients with end-stage renal failure, one on haemodialysis an d the other on continuous ambulatory peritoneal dialysis (CAPD), had been e xposed to lead and developed secondary hyperparathyroidism. An edetate calc ium disodium (EDTA) test was performed in combination with haemofiltration or CAPD before and after parathyroidectomy. Results. Before parathyroidectomy, both patients had low delta aminolaevuli nic acid dehydrase (ALA-D) and high concentrations of chelated lead. After parathyroidectomy, there was a dramatic decrease in chelated lead and the A LA-D returned to normal. Conclusion, Secondary hyperparathyroidism increases mobilization of bone le ad in dialysis patients with an elevated lead burden. This may cause toxic effects.