Hyperparathyroidism (HPT) is a hormonal disorder that occurs when one or more of your four parathyroid glands become enlarged and overactive, causing them to produce excessive amounts of parathyroid hormone (PTH).

About 28 out of 100,000 North Americans develop HPT each year. Twice as many women develop this disease and the incidence increases with age.

Your parathyroid glands are located behind the thyroid gland at the front of your neck. They produce PTH, the hormone that maintains the correct levels of calcium in your blood and bones, helps absorb calcium from food and prevents you from losing too much calcium in your urine.

If you have HPT, too much calcium leaves your bones and collects in your blood. This can result in excess bone loss or osteoporosis as well as other problems such as kidney stones and kidney malfunction.

In 85 percent of people with HPT, a benign tumor, called an adenoma, has formed on one of the parathyroid glands, causing it to become overactive. In most other cases, the excess hormone comes from two or more enlarged parathyroid glands, a condition called hyperplasia. Very rarely, hyperparathyroidism is caused by cancer of a parathyroid gland.

Often people with hyperparathyrodism do not experience any symptoms or attribute them to other causes. Skeletal weakening is one of the classic effects of hyperparathyroidism and may make people susceptible to broken bones. A high blood calcium level also can lead to kidney stones and kidney malfunction. Other common symptoms of hyperparathyroidism include:

  • Loss of appetite
  • Thirst
  • Frequent urination
  • Lethargy and fatigue
  • Muscle weakness
  • Joint pain
  • Constipation
  • Nausea and vomiting
  • Abdominal pain
  • Memory loss

Treatment for hyperparathyroidism is usually surgery to remove the parathyroid tumor (parathyroid adenoma) or parathyroid gland.