Treatment

The aim in secondary hyperparathyroidism is to treat the underlying cause.

• conventional therapy includes dietary modification to reduce phosphate intake, the use of phosphate binders, hydroxylated vitamin D sterols (calcitriol, alfacalcidol) or the synthetic vitamin D analogue paricalcitol, and modification of the dialysis regimen
• in severe hyperparathyroidism, total or partial surgical removal of the parathyroid glands may be required
• cinacalcet is a calcimimetic agent which increases the sensitivity of calcium-sensing receptors to extracellular calcium ions, thereby inhibiting the release of PTH
  • not recommended for the routine treatment of secondary hyperparathyroidism in patients with end-stage renal disease on maintenance dialysis therapy (1)

Notes (1):

• reducing phosphate levels in the diet while maintaining adequate nutritional intake is difficult, because many sources of protein are also high in phosphate.
  • phosphate binders can be taken with meals to reduce phosphate absorption from the gut
    • previously aluminium hydroxide was commonly used as a phosphate binder, but concern about aluminium toxicity in people receiving dialysis means that it is no longer widely used for this purpose
    • calcium acetate and calcium carbonate are the most commonly used phosphate binders, but calcium salts are contraindicated in hypercalcaemia
    • sevelamer is a non-calcium-containing phosphate-binding agents
• vitamin D compounds that do not need renal hydroxylation for activation have been used in the treatment of secondary hyperparathyroidism in patients with end-stage renal disease (ESRD) - however, doses that are capable of suppressing PTH secretion may lead to hypercalcaemia and a decline in renal function. Vitamin D compounds are contraindicated in hypercalcaemia. By increasing intestinal absorption of calcium and phosphate, the risk of vascular calcification may be increased
• in patients with ESRD and receiving dialysis - phosphate clearance can be improved by intensifying the dialysis regimen. The most usual haemodialysis prescription is for 4 hours three times per week. Slow prolonged dialysis (over the course of 8 hours or more at night) or more frequent (daily) dialysis increases phosphate removal. Limitations on the availability of dialysis facilities mean that this option may be feasible only for some patients on home dialysis.
• surgical parathyroidectomy can be subtotal, total, or total with some parathyroid tissue reimplanted in a site such as the arm. Perioperative risk is greater in people with renal failure than in people with normal renal function, and there is the additional risk that any remaining parathyroid tissue will become hyperplastic and require repeat surgery.

Reference:

1. NICE (January 2007). Cinacalcet for the treatment of secondary hyperparathyroidism in patients with end-stage renal disease on maintenance dialysis therapy