From the Guidelines
Hyperparathyroidism is classified into three types: primary, secondary, and tertiary, each with distinct underlying causes and effects on parathyroid hormone (PTH) levels and calcium homeostasis. The differences between these types are crucial for diagnosis and management, as they impact morbidity, mortality, and quality of life.
Primary Hyperparathyroidism
Primary hyperparathyroidism is characterized by the autonomous overproduction of PTH from the parathyroid glands, often due to a benign adenoma, hyperplasia, or rarely carcinoma, leading to hypercalcemia with inappropriately normal or elevated PTH levels 1.
Secondary Hyperparathyroidism
Secondary hyperparathyroidism, on the other hand, develops as a compensatory response to chronic hypocalcemia, commonly seen in patients with chronic kidney disease (CKD) where decreased vitamin D activation and phosphate retention stimulate PTH secretion, resulting in elevated PTH levels with low or normal calcium levels 1.
Tertiary Hyperparathyroidism
Tertiary hyperparathyroidism occurs when longstanding secondary hyperparathyroidism progresses to autonomous PTH secretion, typically in patients with end-stage renal disease, where the parathyroid glands become autonomous and continue to secrete excessive PTH despite normalization of calcium levels, leading to hypercalcemia 1.
- Key factors in managing these conditions include monitoring PTH levels, adjusting therapies such as active vitamin D and phosphate supplements, and considering adjuvant therapies like calcimimetics or parathyroidectomy in certain cases to prevent complications and improve quality of life.
- The management of hyperparathyroidism, especially in the context of chronic diseases like CKD, requires careful consideration of the potential for progression to tertiary hyperparathyroidism and the associated risks of hypercalcemia and bone disease.
- Therefore, accurate diagnosis and appropriate management of primary, secondary, and tertiary hyperparathyroidism are critical to prevent morbidity and mortality, and to improve the quality of life for affected patients.
From the Research
Definition and Causes
- Primary hyperparathyroidism is a condition where one or more parathyroid glands produce excessive parathyroid hormone (PTH) due to adenoma or hyperplasia of the glands 2.
- Secondary hyperparathyroidism is caused by a deficiency in vitamin D or uremia, leading to an increase in PTH levels 2, 3.
- Tertiary hyperparathyroidism occurs when long-standing secondary hyperparathyroidism becomes autonomous, resulting in excessive secretion of PTH and hypercalcemia 2, 3.
Characteristics
- Primary hyperparathyroidism is characterized by hypercalcemia and elevated PTH levels 4, 5.
- Secondary hyperparathyroidism is characterized by normal serum calcium levels and elevated PTH levels 3.
- Tertiary hyperparathyroidism is characterized by hypercalcemia and elevated PTH levels, often occurring in patients with chronic kidney disease after kidney transplant 3.
Treatment
- Primary hyperparathyroidism is typically treated with surgery, which is the only definitive therapy 4, 5.
- Secondary hyperparathyroidism may be treated with vitamin D analogues, such as paricalcitol, and calcium sensing receptor agonists, such as cinacalcet 2.
- Tertiary hyperparathyroidism may be treated with cinacalcet and other medical therapies, although data on management is limited 2, 3.