The American Association of Endocrine Surgeons, Patient Education Site

Parathyroid Glands: What is primary hyperparathyroidism (PHP)?

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What is primary hyperparathyroidism (PHP)?

Primary hyperparathyroidism (PHP) is a disease in which one or more hyperactive parathyroid glands constantly make too much parathyroid hormone (PTH). In primary hyperparathyroidism, the "thermostat" controlling the calcium is always on high. This leads to calcium being taken out of the bones (leading to weakening of the bones or osteoporosis) and gastrointestinal tract and put into the blood stream. This increases the blood levels of calcium. Since the blood is cleaned (filtered) by the kidneys, this leads to the kidneys being exposed to high levels of calcium, which can lead to kidney stones, kidney damage, and other problems. In most patients with primary hyperparathyroidism (80%), only one of the four parathyroid glands is diseased - these people have what is called a "single adenomaAdenoma - A benign, enlarged, and hyperactive parathyroid gland.." In about 10% of affected people, two or three glands are hyperactive- called "double or triple adenoma." Finally, in 10% of patients, all four glands are hyperacitve- called "four gland hyperplasiaFour gland hyperplasia - When all four glands are hyperactive.." About 28 out of 100,000 people will have this disease and it is twice as common in women than men. The disease becomes more common as people get older and most commonly occurs after age 45 with an average age of 65. Primary hyperparathyroidism is the most common cause of abnormally high blood calcium levels in the general population. There are other less common possible causes of a high calcium level in the blood such as secondary hyperparathyroidism (see Secondary Hyperparathyroidism), cancer, too much dietary calcium, etc. If you have high calcium levels, you should work with your healthcare practitioner to figure out the exact cause.

What is the chance that this is parathyroid cancer?

Parathyroid cancer is extremely rare (almost 1 in 2 million people). Cases of parathyroid cancer make up less than 1% of the total number of patients with primary hyperparathyroidism. Patients with parathyroid cancer typically have a very high calcium level (greater than 13 to 14 mg/dL) and a very high PTH level (greater than five times the upper limit of normal, usually 300 pg/mL or more). Often patients with parathyroid cancer will present with a rock hard mass in the neck. The best treatment for parathyroid cancer is an operation to remove both the parathyroid and the thyroid lobe on the same side. Please see the Parathyroid Cancer section for more information.

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