Hyperparathyroidism is when the calcium levels in your blood and tissues are too high.
Primary hyperparathyroidism mean 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.
That can happen due to:
A noncancerous tumor in one of the parathyroid glands. This causes most primary cases.
Two or more of the glands being too active and producing too much of the parathyroid hormone.
Cancer of one of the glands. This is a very rare cause of primary hyperparathyroidism.