The parathyroid glands are four small glands in the thyroid which control the calcium levels in the body: how much is absorbed from our diet, how much is secreted by the kidneys, and how much is stored in our bones.
Although the parathyroid glands form part of the thyroid gland anatomically, they have no related function. The thyroid gland regulates the body’s metabolism and has no effect on calcium levels, while parathyroid glands regulate calcium levels and have no effect on metabolism.
Although the four parathyroid glands are quite small, they are very vascular. This suits them well since they are required to monitor the calcium level in the blood 24 hours a day. 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 parathyroid glands sense it, and increase production of the parathyroid hormone, which calls upon the calcium stored in our bones.
The parathyroid gland tumour
- The parathyroid gland hormone is a protein capable of causing distant cells in the body to react in a specific manner, and has a very powerful influence on the cells of the bones. When one of the parathyroid glands is overactive (hyperparathyroidism), usually indicating a parathyroid tumour, too much of the parathyroid hormone will cause our bones to release calcium constantly into the bloodstream.
- Calcium is the main structural component of bones and gives them their rigidity. Under the presence of the parathyroid gland hormone, bones will give up their calcium to increase the blood level of calcium. Under normal conditions, this process is finely tuned and the amount of calcium in our bones remains at optimum levels. But in the presence of too much parathyroid hormone, bones will continue to release their calcium into the blood at a rate which is too high, causing the bones to lose too much calcium.
- Years of exposure to levels of parathyroid hormone that is too high causes bone depletion of calcium. This results in osteoporosis – brittle bones that are prone to fractures.
- This continued dissolving of central bone is what causes the bone pain so common to hyperparathyroidism. It can contribute to the weakening of the spinal column resulting in the ‘hunched’ appearance of elderly persons.
It is important to note that everyone with parathyroid disease will get osteoporosis. The longer they have a parathyroid tumour, the worse the osteoporosis will be.
There is really only one remedy for hyperparathyroid osteoporosis – and that is the removal of the tumour causing the illness. Once the tumour or bad gland is removed, the osteoporosis will improve, and the increase in bone density is often dramatic. It can be confidently noted, that in most patients suffering a parathyroid tumour, the osteoporosis thus caused is completely reversible once the offending bit has been removed.
The rapid and continuous loss of bone density is halted immediately, and recent studies have shown that the body will restore bone density after the excess hormone is removed. This restoration is a slow process, and the bones may take many years to repair themselves, and they may never regain their previous calcium levels and overall density, but at least from the point of the operation, the body is allowed to begin healing itself.
Supplemental calcium after an operation is also considered a sensible route. There are new drugs which may assist the process of restoring calcium to the bones; these are specifically designed to make bones add calcium to their structure. But it is advisable to discuss the options with your doctor. Remember that drugs such as Fosamax, Actonel, Evista, and Micalcin do NOT work if the tumour has not been removed. However, after the operation you may find them beneficial.
The parathyroid glands are like the filing room in a complex company, always keeping tabs on documents and sending out information. They work very hard, actually – as do your bones who are always trying to keep up with instructions. If you really love your bones, then it’s advisable to wake up every day and be glad that your parathyroid glands – those busy little engines – are healthy and active. Love ‘dem glands!
NOFSA (National Osteoporosis Foundation South Africa)
NOFSA is the only non-profit, voluntary health organisation dedicated to promoting lifelong bone health. We focus on reducing the widespread prevalence of osteoporosis while working to find a cure for the disease, and by supporting research and developing programmes of education and advocacy.
Find out more about our work at: www.osteoporosis.org.za