You have one or more enlarged parathyroid glands. This can cause primary hyperparathyroidism. The parathyroid glands control the calcium level in your blood. Primary hyperparathyroidism causes high levels of blood calcium (hypercalcemia). This can lead to problems all over your body. To treat the problem, the enlarged glands are often removed with surgery. You may need one or more parathyroid glands removed. The decision about how many glands to remove is often made during surgery. Ask your doctor for more information.