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The parathyroid glands are four pea-sized glands, located in the neck, that produce parathyroid hormone (PTH) to regulate the calcium level in our bodies. These glands constantly measure the level of calcium in the blood, and if it drops below normal, they increase production of PTH. When the calcium level increases, they lower production of PTH.

Primary hyperparathyroidism is a disease of the parathyroid glands that occurs when one or more of the glands become enlarged and overactive, producing too much PTH and a rise in the blood calcium level. Too much calcium in the bloodstream can lead to problems affecting bones, the nervous system, kidneys, intestine and muscles.

In most patients (90 to 95 percent), a single gland develops into a benign tumor, known as an adenoma. In the other patients, two adenomas (five percent) or four glands (five percent) enlarge. The latter benign condition is called hyperplasia. Parathyroid cancer is an extremely rare cause of primary hyperparathyroidism (less than one percent).

To help diagnose primary hyperparathyroidism, a physician will use a blood test to check calcium, parathyroid, and vitamin D levels.

The most common symptoms of too much calcium in the blood are fatigue, muscle weakness, joint pains and constipation, loss of appetite, thirst, frequent urination, lethargy. More severe symptoms are nausea and vomiting, abdominal pain, memory loss and depression.

Many patients have no signs or symptoms at all, and they don’t know they have the disorder until their physician notices high calcium levels on a routine blood test. Other diseases and certain medications also can increase blood calcium levels, so a diagnosis of primary hyperparathyroidism can be made only when blood tests show high levels of parathyroid hormone.

In the United States, 28 out of every 100,000 people can be expected to develop primary hyperparathyroidism each year. Women outnumber men by three to one, and the frequency of the condition increases with age.


The cause of primary hyperparathyroidism is unknown in most patients. The only cure is surgical removal of the affected gland or glands. Occasionally, when a patient has multiple other serious medical problems and the blood calcium and parathyroid levels are only mildly elevated, a wait and see approach may be considered, with routine monitoring of calcium levels, kidney function and bone density. The decision about surgery requires careful evaluation and individual assessment.

When an experienced surgeon performs the surgery, as happens at Providence Saint John’s Health Center, it is successful in 97 to 98 percent of cases. Since most patients (90 to 95 percent) have only one tumor, a minimally invasive procedure easily removes the affected gland and the patient does not have to spend the night in the hospital. The trick is finding which gland is the culprit.

To locate an abnormal gland, Providence Saint John’s surgeons use a clinic-based focused head and neck ultrasound and a 3-4D CT scan if needed, which is the newest technology.

Once found, the surgeon performs a minimally invasive operation to remove the affected gland. Parathyroid hormone levels are checked four times during the procedure to assure that the affected gland was removed.  If the hormone levels do not drop appropriately, then the surgeon may convert to a conventional 4-gland surgical approach, identifying the remaining three glands and removing one or two more enlarged glands. The surgeon may do a conventional 4-gland surgical exploration from the start if all of the localization scans were negative.