Overactive parathyroid glands

Hyperparathyroidism – the medical term for having overactive parathyroid glands – is one of the most common hormone disorders. The parathyroid glands are a number of small hormone-producing glands located in the neck behind the thyroid gland, which function independently of the thyroid.

The parathyroid glands regulate the body’s calcium content. For this purpose, they produce parathyroid hormone (PTH) – also called parathormone. If the parathyroid glands become overactive, they produce too much of this hormone. This leads to an increased release of calcium from the bones, which cannot be excreted in full by the kidneys. The level of calcium in the blood then rises. At the same time, more phosphate is excreted in urine, causing the level of phosphate in the blood to decrease.

Around half of all people with overactive parathyroid glands don’t notice any symptoms. For some, however, the symptoms are many and severe, including bone pain, kidney stones, fatigue, anxiety or depression.

Overactive parathyroid glands are often caused by a benign tumor on one of the glands. This form of the condition is much more common in women than in men and becomes more prevalent with age. Other illnesses can also lead to overactive parathyroid glands, such as chronic renal insufficiency, for example.

In many cases, overactive parathyroid glands are surgically removed. The hormone disorder is frequently cured as a result.

A slight increase in the activity of the parathyroid glands often causes no symptoms and is only detected by accident in a routine blood test.

In severe forms of the disorder, the disruption of the body’s calcium levels produces symptoms such as:

• tiredness and muscle weakness
• constipation, loss of appetite or nausea
• gastric and duodenal ulcers
• gallstones
• increased urination and increased thirst
• symptoms caused by kidney stones, such as stabbing pains in the side
• bone and joint pain, sometimes also fractures in the spinal vertebra or feet that cannot be explained by any major injuries or accidents
• itching
• sleep disorders or disrupted sleep patterns, difficulties with concentration, impaired memory
• mood swings or even anxiety and depression
• high blood pressure and cardiac arrhythmias

There are several possible causes for overactive parathyroid glands. Doctors distinguish between primary, secondary and tertiary hyperparathyroidism.

Primary hyperparathyroidism

This is the most common type. Primary means that the disorder originates in the parathyroid glands themselves. In most cases, the cause is a benign tumor on one of the parathyroid glands. Occasionally, two or more glands are affected. These tumors are usually benign (adenomas). They cause increased production of parathyroid hormone (parathormone), which in turn causes symptoms. 

Secondary and tertiary hyperparathyroidism

These types of hyperparathyroidism are caused by other illnesses. Reduced intake of calcium due to a chronic bowel disorder or increased loss of calcium due to chronic renal insufficiency leads to an inadequate level of calcium in the blood. The parathyroid glands attempt to compensate for this and produce increased quantities of parathormone, which releases additional calcium from the bones.

Chronic renal insufficiency in particular is associated with disruptions of the body’s mineral levels and often leads to overactive parathyroid glands. In the long term, the glands begin to grow in size and their increased activity develops a momentum of its own. Doctors refer to this as tertiary hyperparathyroidism.

During the initial stages of the disorder, symptoms may be mild or have other possible explanations. Therefore, doctors will ask patients specific questions about their medical history and symptoms. If it is suspected that the patient has overactive parathyroid glands, various diagnostic tests are then performed. In some cases, a precise diagnosis is made by hormone specialists.

Blood and urine tests

A high level of parathormone in the blood is a typical indicator of overactive parathyroid glands. Frequently, though not always, the calcium level is elevated and the phosphate level is low. 

The patient’s vitamin D level, kidney function and amount of calcium excreted in their urine are also measured.

Bone density measurement

A special X-ray examination determines whether overactive parathyroid glands have already caused a decline in bone density. The spine, hips and forearms are typically examined.

Imaging prior to surgery

If surgery is planned, the parathyroid glands and thyroid gland are examined by means of an ultrasound scan. Doctors also frequently perform a scintigraphy scan. This imaging technique allows them to identify with precision whether there is a tumor on the parathyroid glands and which gland in particular is affected.

In addition, doctors are increasingly using high-resolution computed tomography (CT) of the neck area for planning prior to surgery.

Treatment for overactive parathyroid glands depends on the severity of the disorder and whether the hyperparathyroidism is primary or secondary in nature.

Treatment of primary hyperparathyroidism

This type of hyperparathyroidism is usually due to a benign tumor on a single parathyroid gland. This tumor is surgically removed – usually under general anesthetic. In some cases, minimally invasive surgery with small incisions in the neck is sufficient. The abnormally high hormone level in the blood decreases during the actual procedure, which provides an indicator of successful surgery.

Occasionally, several or all parathyroid glands have to be removed. In some cases, a healthy piece of tissue from the parathyroid glands is transplanted into the neck muscles or the forearm in order to preserve some degree of parathyroid function in the body. Surgery frequently cures the patients’ hormone disorder and allows them to avoid possible complications. 

However, if the hyperparathyroidism is very mild and causes no symptoms, surgery may be avoided and progression of the disorder monitored by means of regular tests.

Treatment of secondary hyperparathyroidism

The main form of treatment for secondary hyperthyroidism is to ensure that the underlying illness (such as chronic kidney disease, for example) is properly treated. It is also important, as a matter of principle, to ensure the healthiest possible balance of minerals and levels of parathormone and vitamin D in the body. 

If the glands have become enlarged, surgery may be considered. This involves full or partial removal of the overactive parathyroid glands. To date, however, no long-term studies have been conducted into the success of this procedure. Therefore, every individual needs to carefully weigh up the risks and benefits of having surgery.