Parathyroid Gland Function

Parathyroid glands try to tightly control the level of calcium in the bloodstream.  They do this by looking at the level of calcium (Ca2+) in the blood stream; if the level is too low they produce PTH, and if the level is too high they stop producing PTH.

Parathyroid Gland Functuion Figure 1

So calcium has a negative effect on the parathyroid glands and causes them to stop producing PTH.  Vitamin D that is activated in the kidney into Calcitriol (or 1,25 (OH) Vitamin D3) also has a negative effect on the parathyroid glands & causes them to stop producing PTH, as well as stop growing.  So activation of Vitamin D in the kidney plays an essential role in the feedback loop that helps finely tune the activity of the parathyroid glands, as well controlling it’s growth.


Primary vs. Secondary Hyperparathyroidism

Primary hyperparathyroidism happens when there is illness primarily or originally in the parathyroid gland or glands themselves; an example is a tumor in a parathyroid gland that produces too much PTH.

Primary vs. Secondary Hyperparathyroidism

Secondary hyperparathyroidism happens when some other medical condition (kidney failure) or deficiency (vitamin D) causes the parathyroid gland to overwork.  As you can see in Figure 1 above, vitamin D both suppresses the parathyroid gland and also prevents it from growing. So when there is too little vitamin D, then the glands overproduced PTH and grows.

In case of kidney failure, there is no kidney to activate vitamin D.  Without activated vitamin D or Calcitriol, as you can see in Figure 1, then again there is no suppression of the parathyroid glands so they both overproduce PTH & continually grow.  Fortunately, if the person that has had kidney failure gets a kidney transplant in time, then their body will produce adequate amounts of activated vitamin D and their parathyroid glands go back to producing normal amounts of PTH and in time shrink down to a normal size.

Secondary vs. Tertiary Hyperparathyroidism

Secondary hyperparathyroidism is due to a factor outside the parathyroid glands causing over-function of the parathyroid glands, and is reversible either with supplementing vitamin D or kidney transplant.

Secondary vs. Tertiary Hyperparathyroidism

However, if the person with kidney failure continues to stay on dialysis for a long period of time and the parathyroid glands continue to grow at some point they may change enough that they may stop looking at the level of calcium or vitamin D in the blood and just keep producing PTH.  These abnormal glands continue to grow and overwork even if the person gets a kidney transplant they don’t go back to normal; this is called tertiary hyperthyroidism.

Tertiary Hyperparathyroidism Symptoms

The symptoms of THPT are similar to those of primary hyperparathyroidism (PHPT). They can include reduced bone density (osteoporosis), fatigue, muscle weakness, bone pain, constipation, abdominal pain, poor concentration, and/or confusion.

Those who experience any of the aforementioned symptoms should seek out medical support. That way, calcium and PTH testing and other assessments can be performed to determine if patients are dealing with any forms of HPT.

Tertiary Hyperparathyroidism Treatment

Parathyroid gland surgery provides a definitive treatment for THPT. During surgery, some or all of a defective parathyroid gland can be removed.

If necessary, a surgeon can remove all four parathyroid glands if they are defective. In this instance, a small portion of healthy parathyroid tissue can be left in place to help the patient maintain a healthy PTH level.

How to Find Out If You Are Dealing with Tertiary Hyperparathyroidism

Those who experience THPT symptoms can meet with Dr. Babak Larian of the CENTER for Advanced Parathyroid Surgery. In doing so, a patient can undergo comprehensive testing to find out if one or more of their parathyroid glands is defective.

Dr. Larian performs a series of tests to assess a patient’s parathyroid glands. If Dr. Larian believes a patient is dealing with THPT or another form of HPT, he may recommend a minimally invasive parathyroidectomy (MIP) to treat their symptoms.

Don’t wait to treat parathyroid gland issues. To schedule a consultation with Dr. Larian, book an appointment online or call us today at 310-461-0300.

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