[Normocalcemic primary hyperparathyroidism: a growing problem]

Normocalcemic primary hyperparathyroidism is at present one of the most common reasons for consultation in bone metabolism units. It is characterized by increased levels of intact parathyroid hormone in the presence of normal serum calcium (total and ionized) in generally asymptomatic individuals. The differential diagnosis should be considered in all situations that occur with secondary hyperparathyroidism. Its natural history is not well known, and it does not always progress to hypercalcemia. As a recently recognized entity, there are still no specific recommendations for its management. In this review we discuss some aspects of this entity, emphasizing the importance of a proper laboratory diagnosis, assessing possible signs or symptoms associated such as kidney stones or osteoporosis, which can help the clinician to take a conservative or interventionist attitude.