Healthtips

The parathyroid glands are four small glands of the endocrine system which are located in the neck just behind the thyroid gland. Although the names of these glands sound similar, their functions are very different. The thyroid gland regulates the body’s metabolism, while the purpose of the parathyroid glands is to regulate the calcium level in our bodies within a very narrow range so that the nervous and muscular systems can function properly. The single major disease of parathyroid glands is over-activity of one or more of them resulting in too much parathyroid hormone causing a dangerous increase in blood calcium levels. This disease is called hyperparathyroidism and the overactive gland is called a parathyroid adenoma. The resulting high calcium levels can result in serious health problems for patients like kidney stones, osteoporosis, gastrointestinal problems, fatigue, mental status changes, and even depression.

By controlling the calcium within the blood in a very tight range, the parathyroid glands also control how much calcium is in the bones, and therefore, how strong and dense the bones are. As the blood filters through the parathyroid glands, they detect the amount of calcium present in the blood and react by making more or less parathyroid hormone (PTH). When the calcium level in the blood is too low, the cells of the parathyroids sense it and make more parathyroid hormone. Once the parathyroid hormone is released into the blood, it circulates to act in a number of places to increase the amount of calcium in the blood (like removing calcium from bones). When the calcium level in the blood is too high, the cells of the parathyroids make less parathyroid hormone (or stop making it altogether), thereby, allowing calcium levels to decrease. This feedback mechanism runs constantly, thereby maintaining calcium (and parathyroid hormone) in a very narrow "normal" range. Under the presence of too much parathyroid hormone, the bones will continue to release their calcium into the blood at a rate which is too high resulting in bones which have too little calcium. This condition is called osteopenia and osteoporosis. When bones are exposed to high levels of parathyroid hormone for several years they become brittle and much more prone to fractures. Another way in the parathyroid hormone acts to increase blood levels of calcium is through its influence on the intestines. Under the presence of parathyroid hormone the lining of the intestine becomes more efficient at absorbing calcium normally found in our diet.

Hyperparathyroidism is a common endocrine disease that affects nearly 1 in 500 women and 1 in 2000 men, most often being discovered in the fifth through seventh decades of like. The disease is frequently picked up when a high calcium level is detected on routine blood testing. Other important causes of high blood calcium must be ruled out such as problems from medications, cancer, and familial disorders. After that is done, a finding of too much parathyroid hormone in the blood indicates that the disease is present.

In 96% of cases hyperparathyroidism is caused by a single overactive gland known as an adenoma but in 3-4% of cases all four glands are involved and this is known as hyperplasia. The out-of-control adenoma is usually not cancerous (less than one in 2500), however, it slowly causes damage to the body because it induces an abnormally high level of calcium in the blood which can affect a number of tissues. Parathyroid adenomas typically are much bigger than the normal pea-sized parathyroid and will frequently be about the size of a walnut. In hyperplasia patients have an enlargement of all four parathyroid glands. In this instance, all of the parathyroid glands become enlarged and produce too much parathyroid hormone. This is much less common but the end results on the tissues of the body are identical. An even rarer situation occurs in less than 1% of the people who have two parathyroid adenomas while having two normal glands. Parathyroid disease will always get worse. It will never go away on its own.

The good news is major advances have been made in parathyroid surgery. New minimally invasive techniques with lower rates of complications than traditional surgical options have been developed. In the past surgeons would explore the neck through a large incision to find the hyperfunctioning gland but now much smaller, more directed outpatient operations are the norm. Tools used during surgery like localizing the abnormal gland with a radiation detecting device called a “gamma probe” and monitoring the amount of parathyroid hormone in the patient’s blood have increased the safety and decreased the time of the procedure.