Primary hyperparathyroidism is a hormonal problem which occurs when one or more of the parathyroid glands produces too much parathyroid hormone. When this occurs, blood calcium is elevated and bones may lose calcium. Surgical removal of the affected gland will cure the disorder. In secondary hyperparathyroidism, a problem such as kidney failure makes the body resistant to the action of parathyroid hormone. Hyperparathyroidism may cause no problems for many years or it may cause problems such as tiredness, weakness, muscle or bone pain, constipation, indigestion, kidney stones, or thinning of bones.
In the USA, about 100,000 people develop the disorder each year. Women outnumber men by 2 to 1, and risk increases with age. In women 60 years and older, 2 out of 1,000 will get hyperparathyroidism.