Background. Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by autonomous production of parathyroid hormone (PTH). Currently, parathyroidectomy (PTX) is considered the main method of PHPT treatment. Its outcome is largely depended on precise preoperative localization of the parathyroid adenoma. Traditional visualization techniques include ultrasound (US), scintigraphy and computed tomography (CT), each of which has its own limitations. In order to improve visualization results positron emission tomography/ computed tomography (PET/CT) with 11C-methionine is used. Objective. To compare the sensitivity and specificity of 11 C-methionine PET/CT with those of conventional imaging techniques for parathyroid adenomas localization.Design and methods. The data of 91 patients diagnosed with PHPT was analyzed. Ultrasound, scintigraphy with 99mTc-sestamib i/99mTc-pertechnetate and CT were performed in 91, 56, and 86 patients, respectively. Since 2020, 11C-methionine PET/CT has been used as the final diagnostic method in 45 patients. Histologу results were used as the benchmark in order to evaluate the diagnostic accuracy of the studied methods.Results. Histological examination confirmed parathyroid adenoma/ hyperplasia in all patients. Multiple adenomas/hyperplasia were found in 5 cases. Ectopic adenomas were detected in 19 patients. The sensitivity of PET/CT with 11C-methionine was 98 %, CT, scintigraphy and ultrasound — 75 %, 79 %, 67 %, respectively. Specificity — 93 %, 73 %, 75 %, 70 %, respectively.Conclusion. 11C-methionine PET/CT showed higher sensitivity and specificity than traditional methods.

Background. The relationships between renin-angiotensin-aldosterone system (RAAS) and elevated parathyroid hormone levels in primary hyperparathyroidism (PHPT) is being actively discussed. But the way how parathyroid hormone interacts with renin and aldosterone currently is not clear. Materials and methods. Forty patients aged 18 to 70 years with a confirmed diagnosis of PHPT were involved in the study. All patients were tested for the main parameters of phosphorus-calcium metabolism and the RAAS parameters (plasma renin, plasma aldosterone) before and 2 weeks after parathyroidectomy. Results. Sixty percent of patients had any cardiovascular disease (CVD) and hypertension was the most common. Patients CVD in comparison with patients without CVD were older (61 and 41 years, respectively; p0.001), had a higher body mass index (28.9 and 21.9 kg/m2, respectively; p0.001) and had a lower aldosterone-to-renin ratio ARR (1.78 and 5.42, respectively; p=0.030). Patients with hypertension were older than patients with normal blood pressure (63 and 41 years, respectively; p0.001), had a higher body mass index (28.1 and 23.5 kg/m2, respectively; p=0.005), a lower ARR (1.46 and 5.82, respectively; p=0.001), as well higher levels of plasma renin (109.2 and 20.3 pg/ml, respectively; p=0.007) and serum total calcium (2.84 and 2.71 mmol/l, respectively; p=0.041). Correlation analysis showed that in patients with PHPT and CVD, the concentration of aldosterone is associated with the level of 24-hour urinary calcium (r=0.829, p=0.042), and in patients with symptomatic PHPT and CVD, the level of aldosterone correlated with the level of ionized calcium (r=-0.812, p=0.05). We found no significant differences between the levels of renin, aldosterone and ARR before and 2 weeks after parathyroidectomy. However, in the postoperative period, there were no differences in the levels of renin and ARR among patients with hypertension and without hypertension. Conclusion. In our study we found that the levels of plasma renin and serum total calcium were higher in patients with PHPT and hypertension compared to patients with normal blood pressure. Also, we found the associations between plasma aldosterone and levels of ionized calcium and 24-hour urinary calcium. But the relationships between RAAS parameters and parameters of phosphorus-calcium metabolism need further investigations.

Fibrocystic osteitis is a rare but severe primary hyperparathyroidism (PHPT) complication. We describe a 66-year-old female presented with fi brocystic osteitis and nephrocalcinosis with eGFR reduction to CKD stage 4 due to primary hyperparathyroidism. Delayed diagnosis of long-term hypercalcemia, high parathyroid hormone level, unsubstituted 25(OH)D defi ciency, and the use of bisphosphonates in high doses caused development of «hungry bones» syndrome in early postoperative period. Severe hypocalcemia required prescription of active and native vitamin D metabolites, oral calcium supplements as well as intravenous calcium. Delay in diagnosis of PHPT with fi brocystic osteitis formation led to lower well-being, reduced quality of life and also provoked sever postoperative hypocalcemia («hungry bone» syndrome).