What is hyperparathyroidism?

The parathyroid glands are four small glands found at the back of the thyroid gland in the neck. The parathyroid glands are responsible for secreting the parathyroid hormone (PTH) into the bloodstream. Hyperparathyroidism is when these glands are too active and secrete more PTH than is healthy.

PTH is responsible for regulating the level of calcium in the bones and bloodstream. When there is too much PTH, calcium is drawn (leached) out of the bones, into the bloodstream and removed by the kidneys. The imbalance of calcium can cause a range of problems, although most people with too much PTH are not aware of their condition.

Hyperparathyroidism is diagnosed in about one of every 1000 men and 2-3 of every 1000 women.

Hyperparathyroidism is an overproduction of the parathyroid hormone into the bloodstream.The parathyroid glands, located at the back of the thyroid gland, secrete parathyroid hormone. 

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Hormone

A chemical substance secreted in one part of an organism and transported to another part of that organism, where it has a specific effect.

Kidneys

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Thyroid

A large gland located in the lower front part of the neck that produces hormones that regulate metabolism, growth and development, especially during childhood.

Causes and types

Primary hyperparathyroidism

This is when a problem with the parathyroid gland itself makes it secrete too much PTH. The most common causes of this is a benign (non-cancerous) tumour (known as an adenoma) in one or more of the parathyroid glands.

In 75-85% of cases, only one gland develops an adenoma [1] . In uncommon cases, all four parathyroid glands are enlarged and over-secreting (a condition known as parathyroid hyperplasia). In rare cases, only two of the glands are enlarged.

Very rarely, the tumour is not benign, but cancerous (parathyroid cancer) [1] .

There are also some cases in which additional parathyroid glands are found in the thyroid area (or, rarely, elsewhere in the body). These can sometimes be the cause of hyperparathyroidism.

Secondary hyperparathyroidism

When a problem in the body, such as chronic kidney problems or vitamin D deficiency, lowers blood calcium levels, the parathyroid gland secretes more PTH.

Secondary hyperparathyroidism is not a medical problem, but a normal response of the body.

Tertiary hyperparathyroidism

When secondary hyperparathyroidism has gone on for a long time, the body has become used to secreting a lot of PTH. The parathyroid glands compensate by secreting too much PTH.

Parathyroid crisis

Also known as 'parathyroid storm', this is a rare medical emergency. It is a complication of primary hyperparathyroidism and is usually associated with a parathyroid cancer, in which blood calcium levels become several times higher than normal. It has serious effects on the brain and nervous system, and requires immediate surgical intervention.

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Cancer

A large group of diseases whose common feature is that they are caused by an uncontrolled growth of the body's cells.

Kidney

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Nervous system

The extensive network of cells and structures that is responsible for activating and coordinating the body's functions, sensory input and cognition.

Thyroid

A large gland located in the lower front part of the neck that produces hormones that regulate metabolism, growth and development, especially during childhood.

Tumour

A growth caused by an abnormal and uncontrolled reproduction of cells.

Vitamin D

A vitamin that is important for the health of bones and teeth as it promotes absorption of calcium from the diet.

Parathyroid cancer

A rare cancer that arises within one or more of the four parathyroid glands located in the neck. These glands produce parathyroid hormone (PTH), a natural chemical that regulates the amount of calcium and phosphate in the bones and blood.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Risk factors

Risk factors for hyperparathyroidism include:

  • A family history of hyperparathyroidism - in about 5% of cases, the condition is inherited.
  • Being female (women are twice as likely as men to have hyperparathyroidism);
  • Older age (over 50 years);
  • Being postmenopausal, and;
  • Having kidney problems.

Kidney

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Postmenopausal

The stage in a woman's life where she no longer experiences menstruation. This is usually defined as occuring 12 months after her last period/menses.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Signs and symptoms

The symptoms of hyperparathyroidism are not easy to detect. Many people with high PTH levels show no symptoms at all, or only mild ones, for a long time.

People with hyperparathyroidism often believe they are feeling fine, but after they are treated, they feel better - their sleep and thinking improve.

Symptoms include:

  • Kidney stones;
  • Bone, joint and muscle pain;
  • Increased risk of fractures;
  • Fractures that happen for no reason (no fall or injury);
  • Thirst;
  • Frequent urination (peeing);
  • Stomach pain;
  • Constipation;
  • Nausea;
  • Loss of appetite;
  • Confusion and difficulty with memory and concentration;
  • Depression;
  • Weakness, fatigue, and;
  • High blood pressure (hypertension).

A mnemonic for symptoms of hyperparathyroidism is 'moans, groans, bones and stones', as they include symptoms of bone aches, kidney stones, stomach pains (moans) and mental changes (groans).

Fatigue

A state of exhaustion and weakness.

Fractures

A complete or incomplete break in a bone.

Joint

A connecting surface or tissue between two bones.

Kidney

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Nausea

A sensation of sickness and unease, typically felt in the stomach, often accompanied by the urge to vomit. Nausea is a common symptom with many possible causes.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Methods for diagnosis

Hyperparathyroidism is diagnosed based on blood test results and symptoms. Your doctor will look for high calcium levels in your blood, low bone density, and calcium build-up in your kidneys (kidney stones).

Because it often shows no symptoms, hyperparathyroidism is most often diagnosed in blood tests that are taken for other purposes.

Blood test

During a blood test, blood can be drawn using a needle or by a finger prick. Your blood can then be analysed to help diagnose and monitor a wide range of health conditions.

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Kidneys

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Bone density

Also known as bone mineral density, it is a measure of bone strength calculated as the mineral content per square centimetre of bone. The higher the mineral content, the denser and stronger the bones.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Types of treatment

Monitoring

If your blood calcium levels are just a little higher than normal, there might be no reason for treatment. In that case, your doctor will suggest monitoring your blood calcium and bone density regularly, and ways you can lower the risk of developing hyperparathyroidism (see the 'Prevention' section below).

Surgery

Surgical removal of the parathyroid gland (parathyroidectomy) is the most effective treatment for hyperparathyroidism. It has a high success rate (95%) [1] and a low chance of complications.

Medication

In cases where surgery is not possible or not recommended, there are medications that can help treat hyperparathyroidism [1] . Bisphosphonates, such as alendronate, help slow the leaching of calcium from bones.

Bisphosphonates

A group of drugs that prevent the loss of bone mass by reducing the normal turnover of bone. They are used to treat osteoporosis and other bone diseases.

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Bone density

Also known as bone mineral density, it is a measure of bone strength calculated as the mineral content per square centimetre of bone. The higher the mineral content, the denser and stronger the bones.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Potential complications

As calcium levels rise, the symptoms listed above become progressively worse. Common complications include:

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Fatigue

A state of exhaustion and weakness.

Kidney

A pair of organs responsible primarily for regulating the water balance in the body and filtering the blood.

Pancreatitis

Inflammation of the pancreas.

Cognitive

Relating to cognition, which are the mental processes and abilities associated with acts of judgement, reasoning and understanding.

Cognitive

Relating to cognition, the mental processes and abilities characterised by knowing and learning.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Prognosis

With treatment, hyperparathyroidism can be successfully cured. The health of bones can improve and the risk of future fractures decreases [1] , but the rate of improvement depends on your age and other medical conditions.

Fractures

A complete or incomplete break in a bone.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.

Prevention

There is not much you can do to prevent hyperparathyroidism, other than being vigilant to the appearance of symptoms. People who are at risk, or have already been diagnosed with mild hyperparathyroidism with no symptoms, can make sure they get enough physical activity and drink enough fluids. They can also watch their calcium and vitamin D intake, making sure that the levels of these two are in the recommendended range.

Calcium

A chemical element, important for many biological functions. Particularly central to maintaining bone and tooth health.

Vitamin D

A vitamin that is important for the health of bones and teeth as it promotes absorption of calcium from the diet.

1. Fraser, W.D. (2009) Hyperparathyroidism. The Lancet 374:145–158.