Hyperparathyroidism is when the calcium levels in your blood and tissues are too high. It happens when your parathyroid glands too much of a chemical called parathyroid hormone.
There are two kinds of hyperparathyroidism:
Primary. This means that your condition is caused by, or starts in, at least one of the parathyroid glands naturally making too much of the hormone that keeps your calcium levels in balance.
Secondary. This means that some other disease or condition is to blame. The common trigger is low calcium levels in the blood, which prompts your body to release parathyroid hormone almost immediately.