Ultrasonographic intervention of parathyroid hyperplasia in chronic dialysis patients: a theoretical approach

Calcitriol pulse therapy has markedly changed the management of secondary hyperparathyroidism in chronic dialysis patients. However, there are still many patients even resistant to this therapy. Our observation of parathyroid size by ultrasonography revealed that these patients usually have enlarged parathyroid glands larger than 0.5 cm3. Such large parathyroid glands are composed of nodular hyperplasia with monoclonal cell proliferation, whose calcitriol receptor density is lower than that of diffuse hyperplasia, thus more resistant to calcitriol. Based on such a pathophysiological model, we have shown that destruction of the largest parathyroid gland was sufficient to restore the responsiveness to calcitriol therapy in these refractory patients. By using colour Doppler ultrasonography, we could also optimize the site and volume of ethanol injection and could detect the recurrence of parathyroid cell growth easily, with lower risk of complications. This selective route of drug delivery to parathyroid glands can be also used for direct injections of calcitriol solution as we have reported. Thus, evaluation of parathyroid size by sensitive ultrasonography is an essential marker for the management of parathyroid hyperfunction in chronic dialysis patients. It is also suggested that ultrasonographic intervention of parathyroid hyperplasia may not only be a useful and safe adjunct to calcitriol pulse therapy, but may also serve as a new therapeutic modality for parathyroid diseases in future.