Hyperparathyroidism is an excess of parathyroid hormone in the bloodstream due to overactivity of one or more of the body's four parathyroid glands. These glands are about the size of a grain of rice and are located in your neck.
The parathyroid glands produce parathyroid hormone, which helps maintain an appropriate balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning.
Two types of hyperparathyroidism exist. In primary hyperparathyroidism, an enlargement of one or more of the parathyroid glands causes overproduction of the hormone, resulting in high levels of calcium in the blood (hypercalcemia), which can cause a variety of health problems. Surgery is the most common treatment for primary hyperparathyroidism.
Secondary hyperparathyroidism occurs as a result of another disease that initially causes low levels of calcium in the body and over time, increased parathyroid hormone levels occur.
Hyperparathyroidism is often diagnosed before signs or symptoms of the disorder are apparent. When symptoms do occur, they're the result of damage or dysfunction in other organs or tissues due to high calcium levels circulating in the blood and urine or too little calcium in bones.
Symptoms may be so mild and nonspecific that they don't seem at all related to parathyroid function, or they may be severe. The range of signs and symptoms include:
- Fragile bones that easily fracture (osteoporosis)
- Kidney stones
- Excessive urination
- Abdominal pain
- Tiring easily or weakness
- Depression or forgetfulness
- Bone and joint pain
- Frequent complaints of illness with no apparent cause
- Nausea, vomiting or loss of appetite
When to see a doctor
See your doctor if you have any signs or symptoms of hyperparathyroidism. These symptoms could be caused by any number of disorders, including some with serious complications. It's important to get a prompt, accurate diagnosis and appropriate treatment.
Hyperparathyroidism is caused by factors that increase the production of parathyroid hormone.
The parathyroid glands maintain proper levels of both calcium and phosphorus in your body by turning the secretion of parathyroid hormone (PTH) off or on, much like a thermostat controls a heating system to maintain a constant air temperature. Vitamin D also is involved in regulating the amount of calcium in your blood.
Normally, this balancing act works well. When calcium levels in your blood fall too low, your parathyroid glands secrete enough PTH to restore the balance. PTH raises calcium levels by releasing calcium from your bones and increasing the amount of calcium absorbed from your small intestine.
When blood-calcium levels are too high, the parathyroid glands produce less PTH. But sometimes one or more of these glands produce too much hormone, leading to abnormally high levels of calcium (hypercalcemia) and low levels of phosphorus in your blood.
The mineral calcium is best known for its role in keeping your teeth and bones healthy. But calcium has other functions. It aids in the transmission of signals in nerve cells, and it's involved in muscle contraction. Phosphorus, another mineral, works in conjunction with calcium in these areas.
The disorder can generally be divided into two types based on the cause. Hyperparathyroidism may occur because of a problem with the parathyroid glands themselves (primary hyperparathyroidism) or because of another disease that affects the glands' function (secondary hyperparathyroidism).
Primary hyperparathyroidism occurs because of some problem with one or more of the four parathyroid glands:
- A noncancerous growth (adenoma) on a gland is the most common cause.
- Enlargement (hyperplasia) of two or more parathyroid glands accounts for most other cases.
- A cancerous (malignant) tumor is a rare cause of primary hyperparathyroidism.
Primary hyperparathyroidism usually occurs randomly, but some people inherit a gene that causes the disorder.
Secondary hyperparathyroidism is the result of another condition that lowers calcium levels. Therefore, your parathyroid glands overwork to compensate for the loss of calcium. Factors that may contribute to secondary hyperparathyroidism include:
- Severe calcium deficiency. Your body may not get enough calcium from your diet, often because your digestive system doesn't absorb the calcium from it.
Severe vitamin D deficiency. Vitamin D helps maintain appropriate levels of calcium in the blood, and it helps your digestive system absorb calcium from your food.
Your body produces vitamin D when your skin is exposed to sunlight, and you consume some vitamin D in food. If you don't get enough vitamin D, then calcium levels may drop.
- Chronic kidney failure. Your kidneys convert vitamin D into a form that your body can use. If your kidneys function poorly, usable vitamin D may decline and calcium levels drop. Chronic kidney failure is the most common cause of secondary hyperparathyroidism.
You may be at an increased risk of primary hyperparathyroidism if you:
- Are a woman who has gone through menopause
- Have had prolonged, severe calcium or vitamin D deficiency
- Have a rare, inherited disorder, such as multiple endocrine neoplasia, type I, which usually affects multiple glands
- Have had radiation treatment for cancer that has exposed your neck to radiation
- Have taken lithium, a drug most often used to treat bipolar disorder
Complications of hyperparathyroidism are primarily related to the long-term effect of too little calcium in your bones and too much calcium circulating in your bloodstream. Common complications include:
- Osteoporosis. The loss of calcium often results weak, brittle bones that fracture easily (osteoporosis).
- Kidney stones. The excess of calcium in your blood may lead to excess calcium in your urine, which can cause small, hard deposits of calcium and other substances to form in your kidneys. A kidney stone usually causes significant pain as it passes through the urinary tract.
- Cardiovascular disease. Although the exact cause-and-effect link is unclear, high calcium levels are associated with cardiovascular conditions, such as high blood pressure (hypertension) and certain types of heart disease.
- Neonatal hypoparathyroidism. Severe, untreated hyperparathyroidism in pregnant women may cause dangerously low levels of calcium in newborns.
In most cases, elevated calcium is detected by blood tests your doctor has ordered as part of a routine screening, a diagnostic work-up for an unrelated condition or a diagnostic work-up to identify the cause of very general symptoms.
Talk to your doctor about test results if they show you have high levels of calcium. Questions you might ask your doctor include:
- Do I have hyperparathyroidism?
- What test do I need to confirm the diagnosis or determine the cause?
- Should I see a specialist in hormone disorders (endocrinologist)?
- If I have hyperparathyroidism, do you recommend surgery?
- What alternatives do I have to surgery?
- I have these 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 overall health, your doctor may ask you questions about possible mild signs or symptoms, including:
- Have you been feeling depressed?
- Do you often feel tired, easily fatigued or generally unwell?
- Are you feeling any inexplicable aches and pains?
- Are you often forgetful, absent-minded or unable to concentrate?
- Have you experienced increased thirst and excessive urination?
Your doctor may ask you additional questions about what medications you're taking and what your diet is like to help determine if you get adequate amounts of calcium and vitamin D.
If the result of a blood test indicates you have elevated calcium in your blood, your doctor will likely repeat the test to confirm the results after you have not eaten for a period of time (fasted).
A number of conditions can raise calcium levels, but your doctor can make a diagnosis of hyperparathyroidism if blood tests show you also have elevated parathyroid hormone.
Additional diagnostic tests
After making a diagnosis of hyperparathyroidism, your doctor will likely order additional tests to rule out possible secondary causes, to identify possible complications and to judge the severity of the condition. These tests include:
Bone mineral density test (bone densitometry). The most common test to measure bone mineral density is dual energy X-ray absorptiometry, or a DXA scan.
This test uses special X-ray devices to measure how many grams of calcium and other bone minerals are packed into a segment of bone.
Urine tests. A 24-hour collection of urine can provide information on how well your kidneys function and how much calcium is excreted in your urine.
This test may help in judging the severity of hyperparathyroidism or diagnosing a kidney disorder causing hyperparathyroidism. If a very low level of calcium in the urine is found, this may indicate a condition that doesn't require treatment.
- Imaging tests of kidneys. Your doctor may order X-rays or other imaging tests of your abdomen to determine if you have kidney stones or other kidney abnormalities.
Imaging tests before surgery
If your doctor recommends surgery, he or she will likely use one of these imaging tests to locate the parathyroid gland or glands that are causing problems:
Sestamibi parathyroid scan. Sestamibi is a radioactive compound that is absorbed by overactive parathyroid glands and can be detected by a scanner that detects radioactivity.
The normal thyroid gland also absorbs sestamibi. To eliminate uptake in the thyroid obscuring the uptake in a parathyroid adenoma, radioactive iodine, which is only taken up by the thyroid, is also given and the thyroid image is digitally subtracted.
Computerized tomography (CT) scanning may be combined with the scan to improve detection of an abnormality.
Ultrasound. Ultrasound uses sound waves to create images of your parathyroid glands and surrounding tissue.
A small device held against your skin (transducer) emits high-pitched sound waves and records the sound wave echoes as they reflect off internal structures. A computer converts the echoes into images on a monitor.
Your doctor may recommend no treatment and regular monitoring if:
- Your calcium levels are only slightly elevated
- Your kidneys are functioning normally, and you have no kidney stones
- Your bone density is normal or only slightly below normal
- You have no other symptoms that may improve with treatment
If you choose this watch-and-wait approach, you'll likely need periodically scheduled tests to monitor your blood-calcium levels and bone density.
Surgery is the most common treatment for primary hyperparathyroidism and provides a cure in about 95 percent of all cases. A surgeon will remove only those glands that are enlarged or have a tumor (adenoma).
If all four glands are affected, a surgeon will likely remove only three glands and perhaps a portion of the fourth — leaving some functioning parathyroid tissue.
Surgery may be done as an outpatient procedure, allowing you to go home the same day. In such cases, the surgery can be done through very small incisions in the neck, and you receive only local anesthetics.
Complications from surgery aren't common. Risks include:
- Damage to nerves controlling the vocal cords
- Long-term low calcium levels requiring the use of calcium and vitamin D supplements
Medications to treat hyperparathyroidism include the following:
Calcimimetics. A calcimimetic is a drug that mimics calcium circulating in the blood. The drug may trick the parathyroid glands into releasing less parathyroid hormone. This drug is sold as cinacalcet (Sensipar).
The Food and Drug Administration approved cinacalcet to treat hyperparathyroidism caused by chronic kidney disease or parathyroid cancer. Some doctors may prescribe it to treat primary hyperparathyroidism, particularly if surgery hasn't successfully cured the disorder or a person isn't a good candidate for surgery.
The most commonly reported side effects of cinacalcet are joint and muscle pain, diarrhea, nausea, and respiratory infection.
Hormone replacement therapy. For women who have gone through menopause and have signs of osteoporosis, hormone replacement therapy may help bones retain calcium. This treatment doesn't address the underlying problems with the parathyroid glands.
Prolonged use of hormone replacement therapy can increase the risk of blood clots and breast cancer. Work with your doctor to evaluate the risks and benefits to help you decide what's best for you.
Some common side effects of hormone replacement therapy include breast pain and tenderness, dizziness, and headache.
- Bisphosphonates. Bisphosphonates also prevent the loss of calcium from bones and may lessen osteoporosis caused by hyperparathyroidism. Some side effects associated with bisphosphonates include low blood pressure, fever and vomiting.
If you and your doctor have chosen to monitor, rather than treat, your hyperparathyroidism, the following suggestions can help prevent complications:
Monitor how much calcium and vitamin D you get in your diet. The Institute of Medicine recommends 1,000 milligrams (mg) of calcium a day for adults ages 19 to 50 and men ages 51 to 70. That calcium recommendation increases to 1,200 mg a day for women age 51 and older and men age 71 and older.
The Institute of Medicine also recommends 600 international units (IUs) of vitamin D a day for adults ages 1 to 70 and 800 IUs a day for adults age 71 and older. Talk to your doctor about dietary guidelines that are appropriate for you.
- Drink plenty of fluids. Drink enough fluids, mostly water, to produce nearly clear urine to lessen the risk of kidney stones.
- Exercise regularly. Regular exercise, including strength training, helps maintain strong bones. Talk to your doctor about what type of exercise program is best for you.
- Don't smoke. Smoking may increase bone loss as well as increase your risk of a number of serious health problems. Talk to your doctor about the best ways to quit.
- Avoid calcium-raising drugs. Certain medications, including some diuretics and lithium, can raise calcium levels. If you take such drugs, ask your doctor whether another medication may be appropriate for you.