Illness caused by the parathyroid glands

The parathyroid glands or epithelial corpuscles, also known as glandulae parathyreoideae, are usually arranged in pairs opposite the thyroid gland in the upper and lower thyroid lobes. However, the »para« already indicates that they are not part of the thyroid gland, but only very close to it. In quite a few cases there are more than four glands, which can also be located in other places further away from the thyroid gland. They are completely independent glands that have nothing to do with the hormones of the thyroid gland. Parathyroid glands significantly regulate a person’s calcium balance via parathyroid hormone (PTH) and are therefore responsible for whether bones remain stable or are pathologically degraded.

Falling calcium blood levels cause the parathyroid glands to release parathyroid hormone. This acts in several places: More calcium is released into the blood from the bones and via reabsorption from the primary urine, and more calcium is also reabsorbed from the intestine. In the kidneys, more vitamin d is converted into its active form. Parathyroid hormone also promotes the excretion of phosphate via the urine, as phosphate hinders calcium absorption. With all these processes, the parathyroid glands ensure that a low calcium level in the blood rises again. 

A sophisticated mechanism that works perfectly as long as the parathyroid glands are healthy. Particularly from the age of 50 and more frequently in women than in men, in some people (after the menopause around 3 per cent of women) one or more of the small glands begin to autonomously produce too much parathyroid hormone. The main effect: the calcium level in the blood rises. Because calcium is not automatically included in a blood count, many of those affected do not even realise that something is wrong with their metabolism. They may feel more tired than before, may have to urinate much more frequently and feel more thirsty, suffer from constipation, bone pain and sometimes nausea. But all of these symptoms can also be passed off as signs of ageing.

Unfortunately, because constantly too much parathyroid hormone causes the bones to lose more and more calcium. It is then no longer just the ageing process that gnaws away at the bones, but another pathological factor, the so-called hyperparathyroidism. This can go unnoticed for years. However, there is an increased risk of bone fractures without the need for trauma from a fall or similar. This is why it is so important to routinely determine calcium levels when people have their check-ups at the doctor. So far, however, this is not standard. 

The normal range for calcium in the blood is very close between 2.20 mmol/l and 2.65 mmol/l. Deviations upwards or downwards should always prompt doctors to ask the patient further questions or carry out tests. The two most important values in this context can be determined simply and easily: the parathyroid hormone and phosphate levels. The doctor should also check the vitamin D level and the kidney values. He can deduce a number of things from the results. A high parathyroid hormone value and a high calcium value together with a low phosphate value and normal kidney values clearly indicate a so-called primary hyperparathyroidism.

Primarily because the cause lies in the parathyroid glands themselves. In 85 percent of cases, one of the glands has developed into an adenoma, an autonomous, benign tumour. In almost 15 per cent of cases, several glands are affected, which is referred to as hyperplasia. In less than one per cent of cases, it is a malignant tumour of a parathyroid gland.

In the case of an adrenal adenoma, an operation to remove the adenoma is now generously recommended. Generously, because the risks are low, but the patient will benefit greatly in terms of their health once their blood calcium is permanently back within the normal range. In asymptomatic patients with only slightly elevated calcium levels, it may also be sufficient to wait.

In the case of multi-gland disease being the cause of high parathyroid hormone levels, doctors look for rare genetic diseases in which several endocrine glands in the body develop benign or malignant tumours. Here too, the affected parathyroid glands are usually surgically removed. However, doctors always leave part of it in the body, as it would be difficult totally without parathyroid hormone.

Whether a parathyroid adenoma is in fact a carcinoma can only be determined after the operation during a histological examination of the altered parathyroid gland. In this case, surgeons also remove the same-sided thyroid lobe and lymph nodes.

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