Endocrine Abstracts

Normocalcaemic primary hyperparathyroidism (NPHPT) is becoming more common nowadays due to the increasing use of screening laboratory methods. In the care of the outpatient office of endocrinology of the 2nd Department of Internal Medicine, Faculty of Medicine, Masaryk University and St. Anne’s University Hospital in Brno in the period between 1 January 2007 and 31 December 2019, there were a total of 304 patients diagnosed with primary hyperparathyroidism. At the time of diagnosis, 249 patients were normocalcaemic (serum calcium levels did not exceed 2.60 mmol/l) and 55 patients were hypercalcaemic. Any secondary causes of hyperparathyroidism were excluded. Two-thirds of patients were in their sixties and seventies at the time of NPHPT diagnosis. The high proportion of NPHPT patients can be explained by the relatively frequent examination of parathyroid hormone levels in normocalcaemia. Nearly one-fifth of all the studied patients with NPHPT had sustained or intermittent pathological increases in serum calcium within 10 years of the onset of the disease (47 patients). NPHPT can be considered a milder form of primary hyperparathyroidism or its initial form. Surgical treatment was recommended for all patients who showed marked hypercalcaemia and who had proven parathyroid adenomas. A similar practice was followed for normokalaemia patients if they also became overtly hypercalcaemic. Parathyroidectomies were also performed in five patients who remained normocalcaemic. In three of these cases, an adenoma was confirmed with MIBI scintigraphy. In two cases, thyroidectomies for nodular goitres were performed. An experienced surgeon performed a targeted search for the parathyroid adenomas in the course of the procedures and removed them after identification. In four cases, there was only a slight increase in calcaemia (up to 2.7 mmol/l) and long-term pharmacological treatment was indicated. Due to significantly reduced bone densities, bisphosphonates were administered. In one patient originally diagnosed with NPHPT, calcium serum levels increased to 3.13 mmol/l within one year of the onset of the disease. Parathyroidectomy was abandoned based on medical contraindication due to polymorbidity. Long-term treatment with cinacalcet was initiated and calcaemia decreased from 3.13 mmol/l to 2.60 mmol/l in four months. Normal calcium serum levels have been maintained for more than nine years.