April 23, 2017
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Hyperparathyroidism

Hyperparathyroidism definition and facts*

*Hyperparathyroid facts medically edited by Melissa Conrad Stöppler

  • Hyperparathyroidism is a condition characterized by overactivity of the parathyroid glands, four small glands located around the thyroid gland in the neck.
  • Primary hyperparathyroidism occurs when there is a disorder of the parathyroid glands themselves.
  • Secondary hyperparathyroidism results when a condition elsewhere in the body affects the parathyroid glands, causing them to produce too much hormone.
  • Normally, the parathyroid glands secrete parathyroid hormone or PTH, a substance that helps maintain the correct balance of calcium and phosphorus in the body.
  • When blood calcium levels fall too low, the parathyroid glands secrete PTH to restore the blood calcium level.
  • Hyperparathyroidism may or may not cause symptoms. When symptoms do appear, they are often mild, such as
  • In primary hyperparathyroidism, the elevated levels of PTH cause elevated levels of blood calcium (hypercalcemia). Increased calcium and phosphorus excretion in the urine may cause kidney stones.
  • The most common cause of primary hyperparathyroidism is a benign tumor called an adenoma on one of the parathyroid glands that secretes too much PTH. In other cases, the excess PTH is produced by two or more enlarged parathyroid glands, a condition called hyperplasia.
  • The diagnosis of hyperparathyroidism relies on blood tests to measure hormone and calcium levels.
  • Surgery is the main treatment for hyperparathyroidism.

What is hyperparathyroidism?

Primary hyperparathyroidism is a disorder of the parathyroid glands, also called parathyroids. "Primary" means this disorder originates in the parathyroids: One or more enlarged, overactive parathyroid glands secretes too much parathyroid hormone (PTH). In secondary hyperparathyroidism, a problem such as kidney failure causes the parathyroids to be overactive. This publication focuses on primary hyperparathyroidism.

What are the parathyroid glands?

The parathyroid glands are four pea-sized glands located on the thyroid gland in the neck. Occasionally, a person is born with one or more of the parathyroid glands embedded in the thyroid, in the thymus, or located elsewhere around this area. In most such cases, however, the glands function normally.

Though their names are similar, the thyroid and parathyroid glands are entirely different glands, each producing distinct hormones with specific functions. The parathyroid glands secrete PTH, a substance that helps maintain the correct balance of calcium and phosphorus in the body. PTH regulates the level of calcium in the blood, release of calcium from bone, absorption of calcium in the intestine, and excretion of calcium in the urine.

When the level of calcium in the blood falls too low, the parathyroid glands secrete just enough PTH to restore the blood calcium level.

Picture of the Parathyroid Glands
Picture of the Parathyroid Glands

What is primary hyperparathyroidism?

If the parathyroid glands secrete too much hormone, as happens in primary hyperparathyroidism, the balance is disrupted: Blood calcium rises. This condition of excessive calcium in the blood, called hypercalcemia, is what usually signals the doctor that something may be wrong with the parathyroid glands. In 85 percent of people with primary hyperparathyroidism, a benign tumor called an adenoma has formed on one of the parathyroid glands, causing it to become overactive. Benign tumors are noncancerous. 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.

This excess PTH triggers the release of too much calcium into the bloodstream. The bones may lose calcium, and too much calcium may be absorbed from food. The levels of calcium may increase in the urine, causing kidney stones. PTH also lowers blood phosphorus levels by increasing excretion of phosphorus in the urine.

How common is hyperparathyroidism?

In the United States, about 100,000 people develop the disorder each year. Women outnumber men two to one, and risk increases with age. In women 60 years and older, two out of 1,000 will develop hyperparathyroidism each year.

Why are calcium and phosphorous so important?

Calcium is essential for good health. It plays an important role in bone and tooth development and in maintaining bone strength. Calcium is also important in nerve transmission and muscle contraction.

Phosphorus is found in all bodily tissue. It is a main part of every cell with many roles in each. Combined with calcium, phosphorus gives strength and rigidity to your bones and teeth.

What causes hyperparathyroidism?

In most cases doctors don't know the cause. The vast majority of cases occur in people with no family history of the disorder. Only about 5 percent of cases can be linked to an inherited problem. Familial multiple endocrine neoplasia type 1 is a rare, inherited syndrome that affects the parathyroids as well as the pancreas and the pituitary gland. Another rare genetic disorder, familial hypocalciuric hypercalcemia, is sometimes confused with typical hyperparathyroidism. Each accounts for about 2 percent of primary hyperparathyroidism cases.

Medically Reviewed by a Doctor on 1/4/2017

Source: MedicineNet.com
http://www.medicinenet.com/hyperparathyroidism/article.htm

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