What do my parathyroid glands do?

Parathyroid glands are part of the endocrine system and they regulate your blood’s calcium levels.

We spoke to an expert consultant endocrine surgeon, Mr Radu Mihai, about their function, symptoms of parathyroid disease and what happens if it is left untreated.
 

What is the function of the parathyroids?

The parathyroid glands are involved in the control of calcium levels in the blood. There are four parathyroid glands, a pair on each side of the neck, just behind/close to the thyroid gland. They are minuscule in size with each normal gland measuring around 4x5x6mm. The cells that make up these glands have a calcium sensing receptor, i.e. a complex mechanism to recognise the levels of calcium in the blood and to stimulate the secretion of parathyroid hormone when calcium levels drop.
 

What could go wrong with the parathyroids?

Similar to other endocrine glands, disease can be caused by excessive or deficient function of the parathyroid glands. For those with excessive function of the parathyroid glands, the most common abnormality is for one gland to enlarge and to secrete more parathyroid hormone (PTH) than necessary.
 

High levels of PTH stimulate the cells that destroy the bone (osteoclasts) to work faster than the cells that repair the bone and therefore there is a constant bone destruction and release of calcium from the bone. This leads to high calcium levels in the blood. This condition is called primary hyperparathyroidism.
 

A less common problem that can occur is when the parathyroid glands get enlarged and overactive in patients with chronic renal failure on dialysis, a condition called secondary hyperparathyroidism. When there is a lack of parathyroid function, the condition is called hypoparathyroidism.
 

The majority of such patients had their parathyroid glands damaged during previous neck surgery, typically during thyroid surgery. Exceedingly rare, the parathyroid glands might be missing from birth due to a genetic condition or might be destroyed during life through an autoimmune process.

What are the signs and symptoms of parathyroid disease?

Patients with primary hyperparathyroidism experience a plethora of symptoms that are suggestive of the disease when they occur together. Each symptom on its own can be due to many other causes but once somebody experiences most/many of these symptoms they need to be assessed for possible primary hyperparathyroidism. Such symptoms include lethargy, tiredness, lack of concentration, poor memory, low mood, aches and pain in large joints, abdominal discomfort and a tendency to constipation. Some patients also have kidney stones and therefore they might suffer with renal colic.
 

There is no correlation between the severity of biochemical abnormalities (i.e. how high are calcium and PTH levels) and the severity of symptoms. Because of this, the absolute value of calcium levels should be used as a criteria for referring for treatment. Surprisingly, some patients with severe primary hyperparathyroidism remain completely asymptomatic. Figure 1 illustrates this point: over 100 patients with primary hyperparathyroidism were asked to estimate the severity of 10 symptoms before the operation and the total score was calculated for each patient; as seen in the figure, the symptoms score varied widely for patients with a range of calcium abnormalities.

Figure 1 - reproduced from WJS 2000

In primary hypoparathyroidism, the lack of PTH makes the body struggle to maintain normal calcium levels. If calcium is too low, it was expected that patients would experience tingling in the hands, fingers or lips and that such symptoms should settle when taking calcium supplements. The reality is far more distressing for many patients. In 2018 I ran a survey of members of HypoParaUK patients support group and over 200 responders assessed their own experience with the condition.

Figure 2 illustrates their replies.
 

On a scale 1–5, highest average scores for severity of symptoms were 4.8 ± 1.8 for fatigue and 4.5 ± 1.9 for low sense of well-being. These were also the most commonly experienced symptoms. Only 4% of patients never experienced fatigue and numbness/tingling sensation while 30–35% experienced these symptoms almost all the time. In addition, 149 patients listed a myriad of associated symptoms rarely described in literature.

What happens if I leave parathyroid disease untreated?

If left untreated, primary hyperparathyroidism will lead to severe bone loss (i.e. osteoporosis) and calcification within the kidney with or without stone formation. Progression to osteoporosis takes many years and therefore some clinicians have questioned if all patients with diagnosis of primary hyperparathyroidism need to be offered surgery to cure their condition. We should explore in a further article who benefits form parathyroid surgery.
 

For those with a lack of parathyroid function, leaving the condition untreated is not an option because the severity of symptoms forces them to pursue daily treatment. Patients with hypoparathyroidism take daily supplements of calcium and vitamin D and those with persistent symptoms are selected for treatment with synthetic PTH. There is increased awareness that more should be done to avoid post-surgical hypoparathyroidism and that the treatment available to such patients should be improved.
 

For more information on treating parathyroid disease, we recommend booking an appointment with a leading consultant endocrine surgeon such as Mr Radu Mihai. Visit his Top Doctors profile today for more information.