Current opinions on nephrolithiasis associated with primary hyperparathyroidism

Nephrolithiasis is a common urological disease and could be secondary to primary hyperparathyroidism (PHPT). PHPT is traditionally characterised with hypercalcaemia. Recently, a normocalcemic PHPT has been officially recognised at the International Workshops. Regarding this new phenotype, nephrolithiasis is frequently found in studies that evaluate low bone mass. However, until now, no study on aetiology of nephrolithiasis considered normocalcemic PHPT. Hypercalciuria related to PHPT is considered as an important risk factor of stone formation in hypercalcemic PHPT, but the precise relationships between hypercalcemic PHPT and nephrolithiasis and between normocalcemic PHPT and nephrolithiasis remain unclear. In patients with hypercalcemic PHPT, after a surgical cure of PHPT, the renal calcium excretion and stone recurrence rate reduce but remain higher above health controls. This finding implies that abnormalities not caused by PHPT also probably affect stone formation. According to the new guideline, the presence of stones indicates the need for parathyroidectomy in patients with either hypercalcemic or normocalcemic PHPT unless contraindications exist. Patients with contraindications for parathyroidectomy or those who do not want to receive parathyroidectomy should be monitored for signs of disease progression and given of medical management. Moreover, due to decreased but significantly higher frequency of nephrolithiasis above those of healthy controls, patients with nephrolithiasis associated with PHPT after parathyroidectomy still should be motivated to explore strategies to prevent stone occurrence.