What are parathyroid glands?
Parathyroid glands are four small glands that are located near the thyroid gland in your neck. They are each about the size of a pea. The parathyroid glands make and release parathyroid hormone (hormones are secretions made by your body to help your body work and keep you healthy).
What is parathyroid hormone (PTH)?
Parathyroid hormone (also called PTH) controls how much calcium is in your blood and within your bones. The release of PTH is turned on and off depending on the levels of calcium in your blood. For example, if the blood level of calcium becomes low, the parathyroid glands will release more PTH. More PTH will cause the bones to release calcium and the blood calcium level will rise.
What is secondary hyperparathyroidism?
Secondary hyperparathyroidism occurs when the parathyroid glands become enlarged and release too much PTH, causing a high blood level of PTH. There are several reasons why this happens in patients with kidney disease:
- Higher blood phosphorus levels
- The kidneys cannot make active vitamin D (needed to absorb calcium)
- Lower blood calcium levels
Secondary hyperparathyroidism can cause bone disease. It can also cause calcium to build up in tissues and organs such as the heart and blood vessels.
How does secondary hyperparathyroidism cause bone disease?
Your bones are in a constant state of change. There are cells that build new bone and cells that remove old bone. This process is known as “bone turnover.” If you have secondary hyperparathyroidism, bone turnover is high. This means that the cells that remove bone are working more quickly than the cells that build new bone, causing your bones to become weak and brittle. This can increase your chances of having bone pain and fractures.
How do you treat secondary hyperparathyroidism?
There are several treatments for secondary hyperparathyroidism including drugs, surgery (an operation), and controlling your blood phosphorus levels.
- Drugs
There are three (3) types of drugs for secondary hyperparathyroidism—vitamin D supplements, active vitamin D (or vitamin D analogs) and cinacalcet. If you have secondary hyperparathyroidism, talk to your healthcare provider about the treatment that is right for you.
Vitamin D Supplements and Vitamin D Analogs
You need active vitamin D to absorb calcium from your intestines into your blood. Without enough active vitamin D, your calcium level drops and the parathyroid glands release too much PTH. Therefore, you will need to take vitamin D supplements if your blood level of vitamin D (also called 25-hydroxy vitamin D) is too low. You may also need a vitamin D analog if your kidneys can no longer make active vitamin D (also called 1,25-dihydroxy vitamin D). Your healthcare provider will tell you the type and amount of vitamin D that is best for you.
Cinacalcet
Cinacalcet is a medicine that acts directly on the parathyroid glands to lower blood PTH. Cinacalcet acts like calcium so the body thinks there is more calcium in the blood. It is a pill that you take once a day and is only for patients on dialysis. Cinacalcet can increase your chances of having low blood calcium levels. - Surgery
Parathyroidectomy is an operation that removes the parathyroid glands. This operation is only for very severe cases of hyperparathyroidism that cannot be managed with medicine. - Controlling Your Blood Phosphorus Levels
Since high blood phosphorus levels increase the release of PTH, it is important to keep your blood phosphorus in normal range using diet and phosphate binders.
