Primary hyperparathyroidism is a disorder of the parathyroid glands, also called parathyroids. Primary means this disorder originates in the parathyroid glands. In primary hyperparathyroidism, one or more of the parathyroid glands are overactive. As a result, the gland releases too much parathyroid hormone (PTH). The disorder includes the problems that occur in the rest of the body as a result of too much PTHfor example, loss of calcium from bones. In the United States, about 100,000 people develop primary hyperparathyroidism each year. 1 The disorder is diagnosed most often in people between age 50 and 60, and women are affected about three times as often as men. 2 Secondary, or reactive, hyperparathyroidism can occur if a problem such as kidney failure causes the parathyroid glands to be overactive. 
What is (are) Primary Hyperparathyroidism ?