Hypercalciuria and hyperparathyroidism — is there always a connection?

Hypercalciuria is a pathological condition characterized by an excess of daily calcium excretion. A high concentration of urine calcium can initiate stone formation. There are several types of hypercalciuria, each requires an individual approach. In the absence of known causes of development, idiopathic hypercalciuria is a frequent dysmetabolic disorder defined as an excess urine calcium excretion with normocalcemia. Resorptive hypercalciuria most often develops due to primary hyperparathyroidism and is caused by elevated PTH and excess release of calcium from bone stores. A thiazide test can be used for differential diagnosis between these conditions. We present a series of clinical cases covered the thiazide test in outpatient practice. The definitive diagnosis is extremely important because it determines the optimal treatment strategy. Secondary hyperparathyroidism (an increase in parathyroid hormone as a result of vitamin D deficiency, chronic renal failure or other conditions) requires medical therapy, while the primary hyperparathyroidism is radically cured only after surgical intervention.Taking into account the prevalence of idiopathic hypercalciuria and primary hyperparathyroidism, it is actual to use the thiazide test more widely in clinical practice.