[What are the actual indications for a surgical parathiroidectomy?].
Secondary hyperparathyroidism (HPTH-II) is a major complication of chronic renal insufficiency (CRI). It affects more than 300,000 dialyzed CRI patients in the world and probably more than 3 million as yet non-dialyzed CRI patients. It results from an imbalance in the interaction between calcium, phosphorus, vitamin D and parathyroid hormone (PTH). In fact, CRI is accompanied by phosphorus retention and this accumulation of phosphorus induces an increased synthesis of FGF-23 (Fibroblast Growth Factor-23) which inhibits the activity of lalpha-hydroxylase and the synthesis of calcitriol. Moreover, the hyperphosphaturia induced by PTH and its stimulant effect on calcitriol synthesis and tubular calcium reabsorption are compromised by the reduction in the expression of the renal PTH receptor. All these changes lead to a negative calcium balance and a reduction in calcium-sensitive receptors and vitamin D receptors in parathyroid cells (CaR), thereby releasing the secretion of PTH and the proliferation of parathyroid cells. The chronic stimulation of PTH by these anomalies causes progressive hyperplasia of the parathyroid cells which may be transformed into a benign tumor with a monoclonal appearance. The usual medical treatment of HPTH-II consists in the correction of hypocalcemia by calcium salts and vitamin D and its derivatives, hyperphosphatemia by lifestyle and dietary changes and intestinal phosphorus chelating agents and metabolic acidosis. Very recently, this treatment armamentarium has been expanded by the advent of the calcimimetic agent, cinacalcet HCl. This product increases the calcium sensitivity of CaR in parathyroid cells leading to a rapid and sustained decrease in PTH secretion. However, it is still necessary to resort to surgical parathyroidectomy (PTX) when these treatments prove to be ineffective or involve risks because of adverse effects and in particular an increase in the calcium-phosphorus ion product and the occurrence or worsening of cardiovascular calcifications. The purpose of this article is to revise the current indications of PTX and to discuss changes and the current and future trends for treatment of HPTH-II by surgery alone or combined.
Torres
Pablo Ureña
PU
Service de néphrologie et dialyse, clinique de l'Orangerie, 11, boulevard Anatole-France, 93300 Aubervilliers, France.
D000089703:Fibroblast Growth Factor-23; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D015994:Incidence; D016030:Kidney Transplantation / Q000502:physiology; D016105:Parathyroidectomy / Q000379:methods*; D006435:Renal Dialysis / Q000009:adverse effects