University of Virginia Health System

The majority of patients with parathyroid disease have a non-familial enlargement of one or more parathyroid glands. There are four parathyroid glands, two on either side of the midline immediately adjacent to the thyroid gland. Each of these parathyroid glands is approximately the size of a pencil eraser and weighs about 30 milligrams. The parathyroid glands secrete a hormone called parathyroid hormone (PTH) which regulates the body's metabolism of calcium. When one or more of the parathyroid glands grows and enlarges for unknown reasons, it produces too much parathyroid hormone. This results in elevated calcium levels in the blood. The calcium stores of the bones can be adversely effected by this situation. This is particularly significant in postmenopausal women subject to osteoporosis.

The patient with a diagnosis of hypercalcemia and primary hyperparathyroidism is usually referred through their primary physician or endocrinologist. The patient with hypercalcemia will require exclusion of a number of differential diagnoses. In a healthy patient (who may or may not have kidney stones), hypercalcemia is usually associated with primary hyperparathyroidism, a disease of the parathyroid glands.

Other disease processes can cause hypercalcemia but are rarely associated with elevated serum PTH levels. Widespread cancer, certain lung diseases, over ingestion of certain vitamins (A & D) can produce hypercalcemia. Rare endocrine diseases (acromegaly) as well as certain familial disorders can also be associated with hypercalcemia. Most of these diagnoses can be quickly and cost effectively ruled out by evaluating certain blood values, which include serum calcium, chloride, and phosphorous levels as well as PTH levels. A chest x-ray is also important to look for signs of additional disease. A 24-hour urinary collection to determine calcium excretion may also be ordered. A referring physician or endocrine surgeon will want to see these values to establish the diagnosis of primary hyperparathyroidism.

In some patients, previous hyperparathyroid surgery has been performed. In that circumstance the endocrine surgeon may want to obtain specific testing for an enlarged parathyroid gland. A sestamibi scan uses radioactive materials in an attempt to locate the enlarged gland or adenoma in the neck or chest area. Additional use of CT or MRI may be necessary to aid in localization. Re-exploration in the neck area may have a higher complication rate due to the scar from the previous surgery.