Parathyroid Hormone and Calcium Levels

The sole purpose of the parathyroid glands is to control calcium within the blood in a very tight range. To do so, the parathyroid glands produce parathyroid hormone to control calcium levels in all of the fluids, cells, surrounding our organs and in our bones.

What Does Calcium Do In The Body?

Calcium is a mineral found in our bodies that is necessary for life. Every cell in our bodies uses calcium to function properly.


  • Calcium is a very strong and versatile element, which is why our bones are made up of calcium. Our bones also act as a storage area for calcium. The bones are constantly absorbing calcium, remodeling themselves, and giving away calcium when the rest of the body needs it (sort of like a savings account).
  • Every cell in the body uses calcium to send messages and communicate with the different parts of the cell.
  • All the nerves in the body use calcium to send signals to the next nerve, muscle or organ (intestines, heart etc…).  This is why calcium imbalance can cause so many neurologic symptoms, including tiredness, anxiety, depression, poor sleep, poor concentration, etc…)
  • Muscles also use calcium to flex, so with calcium imbalance, the muscles either cramp or get weak.

Symptoms of Parathryoid Disease - Dr LarianCalcium is the element that allows the passage of information from one nerve to the next. It allows our nerves to communicate precisely and efficiently, and our nervous system to work. In fact, our entire brain works by fluxes of calcium in and out of the nerve cells. Understanding these functions of calcium helps explain why people can get a tingling sensation in their fingers, or cramps in the muscles of their hands when calcium levels drop below normal. The brain demands normal calcium levels, and any change in the amount of calcium can cause the brain to create emotional and mental imbalances. Too much parathyroid hormone creates high calcium levels, which can leave a person feeling run down, easily irritated, forgetful, depressed, and sleep deprived. All these symptoms are usually relieved once a bad parathyroid gland is removed.

Every cell in the body uses calcium to communicate with the different parts of the cell inside itself. All the nerves in the body uses calcium to send information and commands to the next nerve, muscle, or organ. This is why calcium imbalance can cause so many neurologic symptoms, such as tiredness, anxiety, depression, poor sleep, and poor concentration. Muscles also use calcium to flex, which in turn means that calcium imbalance may cause the muscles to cramp or weaken.

Calcium levels and parathyroid disorder - Dr LarianThis calcium monitoring system runs constantly, thereby maintaining calcium and parathyroid hormone in a very narrow but normal range. Normal parathyroid glands will turn on and off dozens of times per day, in an attempt to keep the calcium level in the normal range so our brain and muscles function properly. Those of us with normal parathyroid function will have calcium levels that are in a very narrow range, with almost no variability (this narrow range is usually much narrower than what is considered to be the range of normal by laboratories for calcium). This can be contrasted with somebody that has a bad parathyroid gland, which has lost its regulatory system. The control system is lost in parathyroid tumors know as hyperparathyroidism, and in general, there is an upward trend in calcium and PTH levels.

What is Parathyroid Hormone?

Parathyroid hormone (PTH) is the hormone released by the parathyroid gland to regulate the levels of calcium in the body.

The way PTH maintains calcium balance is by:

  1. Going to the bones and instructing them to release calcium into the blood (this is the biggest storage area of calcium in the body).
  2. Going to the kidneys and making the kidney get more calcium back from the urine, and also make the active form of Vitamin D (Vitamin D3) which in turn goes to the intestines and helps us absorb more calcium from the food.

There is a very fine control of calcium level in our body by the parathyroid glands.  The body doesn’t like big changes in calcium levels because then the body runs inefficiently, so the parathyroid glands are constantly working to keep the calcium level in the range the body likes.  That range is different for every person and is a narrow range, with occasional high or low numbers that the parathyroid glands quickly correct.   Dr. Strewler discovered this relationship years ago and described it very well in the graphs below.  On graph 2 you can see that a 0.1 mg/dl change in calcium level is met with a 30% change in PTH levels, so the parathyroids react quickly and strongly to changes in calcium.

3 graphs depicting changes in Calcium and PTH


What Happens When You Have A Parathyroid Tumor?

A calcium imbalance in the blood is a sign of parathyroid disease. A tumor develops within a parathyroid gland when there is a disturbance on the sensor of a single parathyroid cell. The set point for the calcium sensor (acting similar to a thermostat) for the calcium changes to a higher number for that particular abnormal cell, while the remaining normal cells stay at the proper sensor calcium level. However, as the calcium in the blood increases, the normal parathyroid cells “turn off,” while the abnormal or bad parathyroid cell continues to produce PTH. The abnormal parathyroid cell begins to multiply and get bigger and the normal cells that are currently not active start to get smaller and shut down. Over time, the calcium level will increase until it reaches the set point on the calcium sensor of the parathyroid tumor cells.  The parathyroid tumor essentially hijacks the calcium balance of the body.

Almost all hyperparathyroid patients experience symptoms of the disease, however, one of the reasons that so many hyperparathyroid patients go undiagnosed or are misdiagnosed is because the symptoms are wide-ranging, are not obvious, and can be associated with several other diseases. As a result, symptoms of hyperparathyroidism can be hard for an inexperienced physician to pinpoint. Some of the debilitating symptoms of hyperparathyroidism include:

  • Weakening of the bones, causing osteoporosis and bone fractures;
  • Kidney stones, which can harm the overall function of the kidney;
  • Sluggish nervous system, leading to fatigue, memory loss, poor concentration, anxiety, and depression;
  • Stiffening of the blood vessels and high blood pressure;
  • Rhythm abnormalities in the heart and heart palpitations;
  • Intestinal issues such as acid reflux and constipation.

But please understand, regardless of the presence or absence of symptoms, the disease is still destroying your body, and ultimately decreasing your life expectancy if not treated. Luckily, the disease can be cured by removing the tumor with a minimally invasive procedure that usually takes less than 20 minutes and can be done under local anesthesia.

Talk To A Parathyroid Expert Today!

If you are suffering from parathyroid disease, contact the CENTER for Advanced Parathyroid Surgery today so we can help you feel like yourself again! Dr. Babak Larian is a parathyroid disease expert who treats patients from around the world. Many of his patients have gone years without being diagnosed properly and upon their first consultation with Dr. Larian are diagnosed with hyperparathyroidism. Dr. Larian will then perform a minimally invasive parathyroidectomy to cure your condition!  We are here to help you.

Consult With Dr. Larian Today.

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