Primary hyperparathyroidism: clinical forms and their features. Retrospective study

Background: Primary hyperparathyroidism (PHPT) is a disease characterized by autonomous production of parathyroid hormone (PTH) from one or more parathyroid glands. Over the past 50 years asymptomatic form of the disease have become more prevalent in developed countries. Aims: To evaluate the clinical forms of PHPT presented in recent years and to specify the clinical and laboratory features in patients with symptomatic and asymptomatic forms of the disease. Materials and methods: We reviewed medical records of 449 patients admitted to three Medical Centers (Saint-Petersburg, Russia) between 2011–2018. Anamnesis, anthropometric data, laboratory (PTH, serum total calcium and ionized calcium, phosphorus, alkaline phosphatase, 24-h calciuria level, 25(OH)D) and instrumental (ultrasonography, scintigraphy, CT/MRI scan, DXA) tests were analyzed. Results: Patients’ average age was 59 years, with 93.1% women, and an F:M ratio of 13.5:1. Symptomatic form of PHPT was identified in 310 patients (69%), while 139 were asymptomatic. 4.2% of patients had PHPT as part of MEN syndrome. Almost half of the male population had urolithiasis and 45% of women had osteoporosis. Cardiovascular diseases were present in 64.4% of cases. 25(OH)D level was determined only in 20% of cases and was higher in asymptomatic patients (32.2 & 18.6 ng/ml, p = 0.003). Normocalcemic form of PHPT was diagnosed in 37 patients (8.2%) and was characterized not only by normocalcemia and lower PHT level, but also by smaller adenoma size ( p = 0.01) and hypocalcemic syndrome after surgery. Conclusions: Study results showed that symptomatic PHPT is more prevalent in the Russian population, that there are gender distinctions affecting the clinical presentation, and that the frequency of cardiovascular disease is high in this patient population. PHPT as part of MEN syndrome was detected in 4.2% of cases and required molecular genetic testing. Normocalcemic form of PHPT with postoperative hypocalcemia was present in every fourth patient. Rare determination of 25(OH)D level imposes the need of mandatory assessment of vitamin D supplementation and the reduction of its deficiency as part of the preoperative preparation of PHPT patients.