Hyperparathyroidism is an excess of parathyroid hormone in the bloodstream due to overactivity of one or more of the body's four parathyroid glands. These oval, grain-of-rice-sized glands are located in your neck. The parathyroid glands produce parathyroid hormone, which helps maintain an appropriate balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning.

Two types of hyperparathyroidism exist. In primary hyperparathyroidism, an enlargement of one or more of the parathyroid glands causes overproduction of the hormone resulting in high levels of calcium in the blood (hypercalcemia), which can cause a variety of health problems. Secondary hyperparathyroidism is a result of another disease that causes low levels of calcium in the body. Surgery is the most common treatment for hyperparathyroidism.

May. 13, 2011