Symptoms of hyperparathyroidism sometimes may be so mild that they're hard to notice. Or the symptoms may seem like they're related to another health concern. If hyperparathyroidism isn't treated, symptoms might get worse over time.

Hyperparathyroidism can cause a range of symptoms, including:

• Urinating much more than usual.
• Often being thirsty.
• Tiring easily.
• Feeling weak.
• Bone and joint pain.
• Belly pain.
• Nausea, vomiting or loss of appetite.
• Constipation.
• Itchy skin.
• Depression.
• Problems concentrating.

Many people with primary hyperparathyroidism don't have symptoms. The condition often is found when a blood test that's done for another reason shows a high level of calcium in the blood.

See your healthcare professional if you have any symptoms of hyperparathyroidism. Those symptoms could be triggered by other health conditions that cause hyperparathyroidism. And some of those conditions can lead to other serious health concerns. It's important to get an accurate diagnosis of hyperparathyroidism as soon as possible, so the cause can be found and treatment can begin right away.

Hyperparathyroidism is caused by factors that raise the amount of parathyroid hormone in the blood.

When they're working correctly, the parathyroid glands help control the levels of calcium and phosphorus in the blood with parathyroid hormone.

• When there's not enough calcium in the blood, the parathyroid glands typically make more parathyroid hormone. The hormone triggers a release of calcium from the bones. It also raises the amount of calcium absorbed by the small intestine from food. The hormone lowers the amount of calcium lost in urine too. Together, these changes raise the amount of calcium in the blood.
• When there's too much calcium in the blood, the parathyroid glands typically make less parathyroid hormone, and the calcium level in the blood drops.

Calcium is best known for its role in keeping teeth and bones healthy. But calcium also helps nerve cells send signals correctly. And calcium helps keep muscles healthy. Phosphorus, another mineral controlled by parathyroid hormone, works along with calcium to keep the body healthy.

If one or more of the parathyroid glands makes a high amount of parathyroid hormone, that condition is hyperparathyroidism. There are two types of hyperparathyroidism: primary and secondary. They have different causes.

Primary hyperparathyroidism

Primary hyperparathyroidism happens because of a health issue with one or more of the parathyroid glands, including:

• A growth on a parathyroid gland that isn't cancer. This is called an adenoma. It's the most common cause of primary hyperparathyroidism.
• Two or more parathyroid glands growing larger than usual. This is called hyperplasia. It causes most of the other cases of primary hyperparathyroidism.
• A tumor that is cancer. This is a rare cause of primary hyperparathyroidism.

Secondary hyperparathyroidism

Secondary hyperparathyroidism happens because of another health condition that lowers the amount of calcium in the blood. This causes the parathyroid glands to make too much parathyroid hormone in an effort to get blood calcium back to a healthy level.

Secondary hyperparathyroidism may be caused by:

• Not enough calcium. Calcium in the body may drop to an unhealthy level if the digestive system can't absorb enough calcium from food. This often happens after surgery on the intestines, including weight loss surgery.
• Not enough vitamin D. Vitamin D helps keep the calcium level in the blood healthy. It also helps the digestive system absorb calcium from food. Sunlight helps the body make vitamin D. There's also some vitamin D in food. If you don't get enough vitamin D, the amount of calcium in the blood may drop.
• Health concerns that affect the kidneys. The kidneys take vitamin D and change it into a form that the body can use. If the kidneys don't work the way they should, the amount of vitamin D that the body can use may go down, and the calcium level drops. Kidney disease that lasts a long time, called chronic kidney disease, is the most common cause of secondary hyperparathyroidism.

In some people with secondary hyperparathyroidism that lasts a long time, the parathyroid glands get bigger. This is often due to end-stage kidney disease. The glands then begin to release parathyroid hormone when the body doesn't need it. The parathyroid hormone level doesn't go down with medical treatment, and the amount of calcium in the blood becomes too high. This is called tertiary hyperparathyroidism.

Risk factors for primary hyperparathyroidism include:

• Being a person who has gone through menopause.
• Having too little calcium or too little vitamin D in your body for a long time. These conditions are called calcium deficiency and vitamin D deficiency.
• Having a rare, inherited disorder, such as multiple endocrine neoplasia type 1, that affects the parathyroid glands.
• Having changes in certain genes that can cause hyperparathyroidism.
• Having radiation treatment on the head or neck.
• Taking the medicine lithium.

Health issues that can happen because of hyperparathyroidism, called complications, are mainly related to the long-term effects of too little calcium in the bones and too much calcium in the blood.

Common complications of hyperparathyroidism include:

• Osteoporosis. Too much parathyroid hormone in the blood causes loss of calcium from bones. That often leads to weak, brittle bones that break easily. This condition is called osteoporosis.
• Kidney stones. Too much calcium in the blood may lead to too much calcium in urine. This can cause small, hard deposits of calcium and other substances to form in the kidneys. Those deposits are called kidney stones.
• Health concerns in the heart and blood vessels. A high level of calcium in the blood is linked to some heart and blood vessel conditions, also called cardiovascular conditions. Examples include high blood pressure; a heartbeat that's too slow, called bradycardia; and a heartbeat that’s not regular, called arrhythmia.

Hyperparathyroidism often is found when a blood test that's done for another reason shows a high level of calcium in the blood. If your healthcare professional suspects that you may have hyperparathyroidism, the following tests can help diagnose it.

Blood tests

If a blood test shows that you have a high level of calcium in your blood, your healthcare professional will likely do the test again.

Many conditions can raise the level of calcium in the blood. But your healthcare professional can diagnose hyperparathyroidism if blood tests show that you have a high level of parathyroid hormone at the same time as you have high calcium.

More testing

After diagnosing hyperparathyroidism, your healthcare professional likely will suggest more tests. These tests can show how serious the condition is. They also can check to see if other conditions might be causing hyperparathyroidism. The tests may be used to see if hyperparathyroidism is leading to other health concerns too. These tests include:

• Bone mineral density test. This test is done to check bone health and to see if bones are weak or brittle, a condition called osteoporosis. The most common test to measure bone mineral density is called dual-energy X-ray absorptiometry (DXA). The test uses an X-ray device to measure how many grams of calcium and other bone minerals are in part of a bone.
• Urine test. Testing a sample of urine collected over 24 hours can show how well the kidneys work and how much calcium is in the urine. If you have hyperparathyroidism, this test can help your healthcare professional see how serious the condition is. The test also can help find health concerns in the kidneys that could be causing hyperparathyroidism.
• Imaging tests of kidneys. An X-ray, ultrasound or other imaging tests of your belly can help show if you have kidney stones or other health concerns involving the kidneys.

Imaging tests before surgery

If you need surgery to treat hyperparathyroidism, one of the following imaging tests may be used to locate the parathyroid glands that are causing the condition:

• Sestamibi parathyroid scan. Sestamibi is a radioactive substance taken up by parathyroid glands when they make too much parathyroid hormone. It can be found by a scanner that detects radioactivity.

  A healthy thyroid gland also takes up sestamibi. To keep the thyroid from blocking the view of the parathyroid glands on an image, this test also includes taking radioactive iodine. Only the thyroid takes up iodine. This allows the person reading the scan to tell the difference between the thyroid gland and the parathyroid glands.

  Computerized tomography (CT) scanning may be combined with the sestamibi scan to make it easier to see any issues with the parathyroid glands.

• Ultrasound. Ultrasound uses sound waves to create images of the parathyroid glands and the tissue around them. A small device held against the skin, called a transducer, sends out high-pitched sound waves. It then records the sound wave echoes as they bounce off organs or tissue in the body. A computer turns the echoes into images on a screen.

Treatment for hyperparathyroidism can include watchful waiting, surgery and medicines.

Watchful waiting

Sometimes, a healthcare professional may suggest no treatment right away for primary hyperparathyroidism, but regular checkups instead. This is called watchful waiting or medical monitoring.

Watchful waiting may be used if:

• Your calcium level is only a little higher than usual.
• Your kidneys are working well, and you have no kidney stones.
• Your bone density is within the standard range or only slightly below that range.
• You have no other symptoms that may get better with treatment.

If you choose watchful waiting, you'll likely need regularly scheduled tests to check the amount of calcium in your blood, your bone density and how well your kidneys are working.

Surgery

Surgery is the most common treatment for primary hyperparathyroidism. It often cures the condition. A surgeon removes the parathyroid glands that are larger than usual or that have a tumor.

If all four parathyroid glands are affected, a surgeon will likely remove only three glands and perhaps part of the fourth. That leaves some parathyroid tissue behind that still works.

Surgery may be done as an outpatient procedure. That means you don't need to stay overnight in a hospital, and you can go home the same day you have surgery. An outpatient surgery often is done with very small cuts, called incisions, in the neck. Local anesthetics are used to numb the neck only.

Health issues that happen because of this surgery, called complications, aren't common. Risks include:

• Damage to the nerves that control the vocal cords.
• A low level of calcium in the blood that lasts after surgery due to removal of or damage to all the parathyroid glands. In this situation, the body can't make enough parathyroid hormone to keep the calcium at a healthy level.

Medicines

Medicines to treat hyperparathyroidism include:

• Calcimimetic. This is a medicine that mimics calcium in the blood. Taking this medicine may cause the parathyroid glands to make less parathyroid hormone. The medicine is sold as cinacalcet (Sensipar).

  Cinacalcet may be used to treat primary hyperparathyroidism when surgery hasn't successfully cured the condition or in people who can't have surgery.

  Cinacalcet may be used along with prescription forms of vitamin D to treat secondary hyperparathyroidism in people who have health conditions involving the kidneys. These medicines help keep a healthy balance of calcium and phosphorus in the body so that the parathyroid glands don't have to work too hard.

• Bisphosphonates. Bisphosphonates prevent the loss of calcium from bones. That may ease osteoporosis caused by hyperparathyroidism. This medicine doesn't treat health issues in the parathyroid glands. That means the calcium level in the blood stays high.
• Hormone replacement therapy. For people who have gone through menopause and have signs of osteoporosis, hormone replacement therapy may help keep calcium in the bones. But this treatment doesn't address the underlying problems with the parathyroid glands.

Talk with your healthcare professional and pharmacist about benefits and potential side effects.

If you and your healthcare professional have chosen watchful waiting for hyperparathyroidism, the following suggestions may help prevent other health concerns from developing:

• Watch how much calcium and vitamin D you get in your diet. Limiting how much calcium you eat or drink is not recommended for people with hyperparathyroidism.

  The daily recommended amount of calcium for adults ages 19 to 50 and men ages 51 to 70 is 1,000 milligrams (mg) of calcium a day. The daily calcium recommendation goes up to 1,200 mg a day for women age 51 and older and men age 71 and older.

  The daily recommended amount of vitamin D is 600 international units (IUs) of vitamin D a day for people ages 1 to 70. It is 800 IUs a day for adults age 71 and older. Talk to your healthcare professional about how much calcium and vitamin D you need.

• Drink plenty of fluids. Drink enough fluids, mostly water, to make your urine look almost clear. This lowers the risk of kidney stones.
• Exercise regularly. Regular exercise, including strength training, helps keep your bones strong. Talk to your healthcare professional about the type of exercise that's best for you.
• Don't smoke. Smoking can weaken bones. It also raises the risk of other serious health problems. If you smoke, talk to your healthcare professional about the best ways to quit.
• Don't take medicines that raise your calcium level. Certain medicines, including some diuretics and lithium, can raise the level of calcium in the blood. If you take these medicines, ask your healthcare professional whether you can switch to something else.

A high level of calcium often is found when a blood test is done as part of a routine screening, tests for another condition or tests to find the cause of general symptoms.

Talk to your healthcare professional about your test results if they show that you have a high level of calcium in your blood. Questions you might ask include:

• Do I have hyperparathyroidism?
• What test do I need to confirm the diagnosis or find the cause?
• Should I see a specialist in hormone disorders? This specialist is called an endocrinologist.
• If I have hyperparathyroidism, do you recommend surgery?
• What treatment can I have other than surgery?
• I have other health conditions. How can I best manage them together?
• Do you have printed material about hyperparathyroidism that I can take home?

To understand the effect of hyperparathyroidism on your health, your healthcare professional may ask you questions about symptoms, including:

• Have you been feeling depressed?
• Do you often feel tired? Do you tire easily? Do you feel generally unwell?
• Are you feeling any unexplained aches and pains?
• Are you often forgetful, absent-minded or unable to concentrate?
• Are you often thirsty?
• Do you urinate more than usual?

Your healthcare professional also may ask you questions about the medicines you take and what your diet is like. This information can help your healthcare professional see if you are getting enough calcium and vitamin D.