PRIMARY HYPERPARATHYROIDISM, WITH A FOCUS ON MANAGEMENT OF THE NORMOCALCEMIC FORM: TO TREAT OR NOT TO TREAT?

Objective: The aim of this study was to determine reasonable care for normocalcemic primary hyperparathyroidism (NCPHPT) patients treated at the endocrine clinic. Methods: The study is based on 218 outpatient cases of primary hyperparathyroidism (PHPT), 187 (86%) of whom were NCPHPT. Subjective complaints, biochemical tests, imaging, and treatment outcome for NCPHPT patients were monitored and compared with the same parameters in patients with hypercalcemic hyperparathyroidism. The number of patients with newly diagnosed NCPHPT who became hypercalcemic and the time period in which it happened were also recorded. Results: Over 6 years of study, in total, 36 of 187 originally normocalcemic patients became hypercalcemic (19%); 24 of 36 within 2 years and 2 of 36 later than after 4 years. Sestamibi scintigraphy was performed in 103 normocalcemic patients (adenoma was detected in 5 cases) and in 46 hypercalcemic patients with pathologically elevated serum calcium levels at the time of assessment (adenoma was detected in 32 of 46 cases). Surgery was performed in 33 patients, 11 of whom were originally normocalcemic (i.e., 6% of all 187 originally normocalcemic patients), and 22 were hypercalcemic from the outset (i.e., 71% of all 31 originally hypercalcemic patients). Conclusion: Some NCPHPT patients converted to hypercalcemic, mostly within 2 years, but some after 4 years or later. Normocalcemic patients should be monitored on a long-term basis, as it is impossible to anticipate when and which normocalcemic patients will become hypercalcemic. Imaging is much less effective in normocalcemic than in hypercalcemic patients.