Hyperparathyroidism

Introduction

Hyperparathyroidism is an overproduction of parathyroid hormone (PTH) by the parathyroid gland. This causes a disturbance in the body's regulation of calcium and phosphorus.

Hyperparathyroidism can be caused by one of two primary conditions− hyperplasia, in which extra parathyroid tissue is produced in the body; or adenoma, in which one or more benign (non-cancerous) tumors form on the parathyroid glands.

The end result is that your body has too much PTH, which causes increased levels of calcium to build up in the blood, resulting in an abnormally high level of calcium in the blood. In most cases, hyperparathyroidism is caused by an inherited disorder called primary hyperparathyroidism. This condition usually affects older adults, though it can affect people at any age.

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Hyperparathyroidism can also be part of multiple endocrine neoplasia type 1 (MEN1), a rare genetic disease that can also cause tumors on other endocrine glands, such as the thyroid gland and pancreas.

Hyperparathyroidism generally does not cause symptoms until calcium levels get extremely high. When this happens, symptoms include weakness and muscle pain due to calcium buildup in the bones and kidneys, kidney stones that can cause pain in your lower back or abdomen, and abnormal heart rhythms (arrhythmias). If left untreated, hyperparathyroidism can lead to bone loss and osteoporosis.

Types of Hyperparathyroidism

There are three main types of hyperparathyroidism −

• Primary hyperparathyroidism

  Primary hyperparathyroidism is a condition that affects the parathyroid gland. It occurs when calcium levels become too high and the parathyroid gland produces too much of the hormone known as parathyroid hormone (PTH). PTH triggers the body to release calcium from bones and other tissues into the blood, which raises blood calcium levels even higher than normal. When this happens, it can cause serious medical problems, including weakness, confusion, constipation, bone loss, and kidney stones.

  In most cases, primary hyperparathyroidism is caused by an autoimmune disease that triggers inflammation of the parathyroid glands. This condition is called autoimmune primary hyperparathyroidism or autoimmune pseudohypoparathyroidism. When this happens, the immune system mistakenly attacks healthy tissue in the body and causes it to grow abnormally. In some cases, no cause can be found for primary hyperparathyroidism.

  Primary hyperparathyroidism usually affects people ages 60 to 70. Women are more likely than men to have this condition. The more children you have, the greater your chance of developing primary hyperparathyroidism because a woman's body produces less estrogen after each pregnancy, which makes hormone-producing glands in her body work less efficiently.

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• Secondary hyperparathyroidism

  Secondary hyperparathyroidism (SHPT) is a disease that can lead to bone loss, kidney stones, osteitis fibrosis cystica, and even death. Although rare, the condition is an important cause of hypercalcemia (excess calcium in the blood) in adults. SHPT is caused by abnormally high levels of parathyroid hormone (PTH), which is released by the parathyroid glands located in the neck.

  The most common cause of SHPT is a parathyroid gland tumour. Other causes include cancer, surgery, radiation, and medications. SHPT can also be caused by other conditions, such as vitamin D resistance, sarcoidosis, and chronic kidney failure. The disease occurs more commonly in people over 50 years old, especially among postmenopausal women. The symptoms vary but include fatigue, muscle weakness and pain, nausea and vomiting, abdominal pain, and constipation or diarrhoea.

• Tertiary hyperparathyroidism

  Tertiary hyperparathyroidism is a rare form of parathyroid disease which occurs when there are multiple parathyroid glands affected by a tumour. Tertiary hyperparathyroidism is caused by a single parathyroid gland tumour that has spread to other glands, usually on the surface of the thyroid gland or nearby lymph nodes.

  Tertiary hyperparathyroidism is more common in women than men, and it usually occurs in people over age 50. The average age at diagnosis is about 65 years old.

  Tertiary hyperparathyroidism can be caused by a number of different types of tumours, but most commonly, it's caused by−

  A benign tumour is called an adenoma (a tumour made up of cells that resemble normal tissues). These tumours are most often found in women over age 40 and men over 50 years old.

  A cancerous tumour is called adenocarcinoma (a tumour made up of cancerous cells). These tumours are most often found in women between the ages of 60-70 years old and men over 70 years old.

Causes of Hyperparathyroidism

Located behind the thyroid in the neck, the parathyroid glands are a group of four tiny glands. As a result, they're commonly referred to as "the calcium glands" because they release a hormone that helps regulate blood calcium levels. The four parathyroid glands match up with their own specific thymus gland (hence the name). When there are too many or too few parathyroid glands, it causes problems with calcium regulation.

Parathyroid disorders can be caused by genetic disorders, cancer, and a number of other factors. The most common cause is an injury or surgery to remove one of the parathyroid glands. As you might expect, this leads to problems with calcium regulation. Also, some people develop tumours on their parathyroids; when these become large enough to press against other organs, they can cause symptoms of hyperparathyroidism.

Typically, a blood test that gauges the blood's calcium content is used to diagnose parathyroid disorders. If you have symptoms of hyperparathyroidism and the test comes back normal, then you will likely be referred to a surgeon who specializes in endocrine disorders.

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The surgeon will examine your neck to see if there are any tumours or other abnormalities visible; if not, he will take a needle biopsy of the gland(s). This test involves inserting a needle into the parathyroid tissue and taking samples; it is not painful and poses no risk to your health.

Symptoms of Hyperparathyroidism

Hyperparathyroidism can lead to several different kinds of problems−

• Bones can become weak and fragile. This can result in bone fractures and osteoporosis.

• The heart muscle may weaken and enlarge (cardiomyopathy).

• Kidney function may be affected, resulting in kidney stones or kidney failure.

• High blood pressure (hypertension) may develop.

• Nerve problems may develop, leading to numbness and tingling in the hands and feet (peripheral neuropathy).

• Anemia may develop due to low levels of iron in the blood (iron deficiency anaemia).

Conclusion

In conclusion, hyperparathyroidism is a condition that can be caused by a number of things, including benign tumours and cancer. It is important to get checked by a doctor if you think you may have this condition, as it can lead to a number of serious health complications.

FAQs

1. How common is hyperparathyroidism?

Hyperparathyroidism affects about 1 percent of all people 50 years old or older, but most people with hyperparathyroidism are unaware that they have it until symptoms develop or someone finds an enlarged parathyroid gland during an examination or test for another condition.

2. What causes hyperparathyroidism?

An adenoma, a benign tumour that develops on one of the four parathyroid glands in your body, is the most frequent cause of hyperparathyroidism. Most adenomas cause no symptoms, but some may grow large enough to cause hyperparathyroidism. Your doctor may find an adenoma during a physical exam or imaging test for another problem, or you may be diagnosed with this condition after an abnormal blood test result is reported by your doctor.

3. How does hyperparathyroidism affect my body?

If you have hyperparathyroidism, it can lead to high blood levels of calcium, low blood levels of phosphorus, and other abnormalities in your blood test results, like increased alkaline phosphatase levels (ALP).

4. What are the symptoms of hyperparathyroidism?

The symptoms of hyperparathyroidism include bone pain, weakness, muscle spasms, cramps, and loss of appetite. Other possible symptoms include fatigue, numbness or tingling in the arms or legs, depression, and dementia.

5. How is hyperparathyroidism diagnosed?

If you have some or all of these symptoms and have had a test that shows high levels of calcium in your blood (a condition called hypercalcemia), then your doctor may suspect that you have hyperparathyroidism and order additional tests to confirm this diagnosis.

In addition to a blood test for calcium levels, these tests might include an ultrasound exam or a needle biopsy to see if one or more of your parathyroid glands are enlarged and producing too much hormone. If one or more of these tests shows that you have hyperparathyroidism, then your doctor will treat the condition with surgery.