Hyperparathyroidism is a disorder in which the parathyroid glands in your neck produce too much parathyroid hormone (PTH).
The parathyroid glands are located in the neck, near or attached to the back side of the thyroid gland. They produce parathyroid hormone. This hormone controls calcium, phosphorus, and vitamin D levels in the blood and bone.
When calcium levels are too low, the body responds by making more parathyroid hormone. This hormone causes calcium levels in the blood to rise, as more calcium is taken from the bone and reabsorbed by the intestines and kidney.
One or more of the parathyroid glands may grow larger. This leads to too much parathyroid hormone (a condition called primary hyperparathyroidism). Most often, the cause is not known.
The disease is most common in people over age 60, but it can also occur in younger adults. Hyperparathyroidism in childhood is very unusual.
Women are more likely to be affected than men.
Radiation to the head and neck increases the risk.
Rarely, the disease is caused by parathyroid cancer.
Medical conditions that cause low blood calcium levels or increased phosphate levels can lead to secondary hyperparathyroidism. Common causes include:
Conditions that make it hard for the body to remove phosphate
Blood tests will be done to check for increased levels of parathyroid hormone (PTH), calcium, and alkaline phosphatase, and lower levels of phosphorous. A 24-hour urine collection test can help determine how much calcium is being removed from the body.
Bone x-rays and bone mineral density (DXA) tests can help detect bone loss, fractures, or bone softening.
X-rays, ultrasound, or CT scans of the kidneys or urinary tract may show calcium deposits or a blockage.
If you have mildly increased calcium levels from primary hyperparathyroidism and you do not have symptoms, you may choose to have regular checkups or get treated.
If you decide to have treatment, it may include:
Drinking more fluids to prevent kidney stones from forming
Avoiding thiazide-type diuretics ("water pills")
Having surgery to remove the overactive glands (recommended for people under age 50)
If you have symptoms or your calcium level is very high, you may need surgery to remove the parathyroid gland that is overproducing the hormone.
Treatment for secondary hyperparathyroidism depends on the cause. Your doctor may suggest:
A special form of prescribed vitamin D, if you have low vitamin D levels
Patients whose hyperparathyroidism is caused by kidney failure may be treated with:
Extra calcium and vitamin D
Avoiding phosphate in the diet
The medicine cinacalcet (Sensipar)
Dialysis or a kidney transplant
Parathyroid surgery, if the parathyroid levels become uncontrollably high
The outlook depends on the type of hyperparathyroidism.
Long-term problems that can occur when hyperparathyroidism is not well controlled include:
Increased risk of bone fractures
High blood pressure and heart disease
Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap. 28.
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.