Hyperparathyroidism is a disease that causes your parathyroid glands to make too much parathyroid hormone (PTH). The parathyroid glands are 4 small glands in your neck that make PTH. They are called 'parathyroid' because they are next to your thyroid gland.
PTH controls how much calcium is in your blood and bones. Your body's levels of calcium, vitamin D and phosphorus all need to be in balance. If they are out of balance (meaning one is higher or lower), your parathyroid glands make more PTH to try to "fix" the balance. For example:
Chronic kidney disease patients are at risk of developing secondary and tertiary hyperparathyroidism. So regular monitoring of blood levels of calcium, phosphorus and parathyroid hormone are important.