[Normocalcemic primary hyperparathyroidism].

We have treated 68 cases of primary hyperparathyroidism (PHPT), among which there were 6 cases (1 male, 5 females) whose calcium levels fell within the normal range. However, in all these cases the serum ionized calcium (Ca++) levels and the serum ionized calcium/calcium ratio (Ca++/Ca ratio) were high. Moreover, in comparing them with hypercalcemic patients (62 cases), the serum Ca++ levels were significantly lower, but the (Ca++/Ca ratio) was significantly higher. Also, the excised weight of normocalcemic patients was significantly smaller than that of hypercalcemic patients. Preoperative locations showed significantly lower levels in comparison with hypercalcemic patients. Based on our study we concluded that even when serum Ca levels fall within the normal range, in multiple and recurrent stone formers, regardless of the presence or absence of local diagnosis, if the serum Ca++ level and Ca++/Ca ratio are high, since the existence of PHPT must be suspected, it is necessary to perform surgery.