Primary hyperparathyroidism due to vitamin D deficiency

Primary hyperparathyroidism is a disease that is often accompanied by hypercalcemia and can have a wide range of clinical manifestations, including atypical symptoms. One of the causes of primary hyperparathyroidism is parathyroid adenoma, the diagnosis of which is complicated by concomitant vitamin D deficiency. The aim was to analyze the diagnostic process in a patient with primary hyperparathyroidism and vitamin D deficiency, and to emphasize the importance of a multidisciplinary approach in the management of such patients. The study included a clinical case analysis of a 49-year-old patient who presented with isolated dermatological complaints. A comprehensive laboratory and instrumental examination was performed (biochemical blood test, hormonal studies, ultrasound, MRI, densitometry). Significant vitamin D deficiency (9 nmol/L), elevated parathyroid hormone (139 pg/mL), hypercalcemia (3.9 mmol/L), and decreased phosphorus were detected. A parathyroid adenoma was visualized. Initial treatment with vitamin D had little effect, confirming the primary nature of the hyperparathyroidism. The patient was referred for surgical removal of the adenoma. Therefore, primary hyperparathyroidism can mask secondary hyperparathyroidism in patients with vitamin D deficiency, which complicates diagnosis. This case highlights the importance of a comprehensive approach, including the role of an endocrinologist, surgeon, and dietitian, for timely detection and effective treatment of the disease. Surgery remains the mainstay of treatment to prevent complications, including osteoporosis and cardiovascular disorders.