What is hyperparathyroidism?
Hyperparathyroidism is a condition in which one or more of your parathyroid glands become overactive and release (secrete) too much parathyroid hormone (PTH). This causes the levels of calcium in your blood to rise, a condition known as hypercalcemia.
What are the parathyroid glands?
Your parathyroid glands secrete PTH to help control the levels of calcium and phosphorous in your body. You have four parathyroid glands, located on the outside borders on the backside of your thyroid gland. Your thyroid gland is located on the front of your neck.
What happens when there’s too much parathyroid hormone (PTH) circulating in my body?
If you have an overactive parathyroid, one or more of your parathyroid glands makes too much parathyroid hormone (PTH). Too much PTH signals your body to make more calcium available. Your body responds by:
- Releasing more calcium into your blood from your bones (where most of your calcium is stored). Loss of calcium from your bones weakens them and increases your risk of a fracture.
- Having your digestive tract absorb more calcium from the foods you eat.
- Having your kidneys retain calcium and return it to your blood instead of flushing it out in your urine. Too much calcium in your kidneys can cause kidney stones to form.
Who gets hyperparathyroidism?
Approximately 100,000 people develop hyperparathyroidism in the United States every year. Older women who are postmenopausal are at the highest risk for the condition.
Symptoms and Causes
How does hyperparathyroidism occur?
There are two types of hyperparathyroidism, primary and secondary:
- In primary hyperparathyroidism, your parathyroid glands make too much PTH, which causes the level of calcium in your blood to rise.
- In secondary hyperparathyroidism, the overactivity of the parathyroid glands occurs in response to another condition that’s causing calcium loss. Parathyroid overactivity is an attempt on your body’s part to keep the calcium levels normal. Examples of conditions that lower calcium levels include kidney failure, severe vitamin D deficiency and severe calcium deficiency.
Causes of primary hyperparathyroidism include:
- A noncancerous (benign) growth, called an adenoma, forms on a single parathyroid gland. The adenoma causes the gland to overact and make more PTH. This is the most common cause.
- Two or more of your parathyroid glands become enlarged, a condition called hyperplasia, and produce too much hormone.
- Radiation treatment to the neck area.
- Inherited conditions, such as multiple endocrine neoplasia type 1. This is a rare cause.
- Cancer of a parathyroid gland (rare).
What are the symptoms of hyperparathyroidism?
If you have early hyperparathyroidism, you may not have any symptoms. If you have mild hyperparathyroidism, you may have some of the following symptoms:
- Joint pain.
- Muscle weakness.
- Feeling tired.
- Trouble concentrating.
- Loss of appetite.
If your hyperparathyroidism is more severe, you may have these symptoms:
- Nausea and vomiting.
- Confusion, forgetfulness.
- Increased thirst and need to urinate.
- Bone pain.
Other problems associated with severe hyperparathyroidism include:
Diagnosis and Tests
How is hyperparathyroidism diagnosed?
Because the symptoms of hyperparathyroidism can be nonexistent, mild or common to many other disorders, a diagnosis of hyperparathyroidism can be missed. Often, the condition is discovered through a blood test that is ordered for another condition.
If you have primary hyperparathyroidism, your blood test will show a higher-than-normal levels of calcium and parathyroid hormone. Your provider may order a sestamibi scan to check for any growths on your parathyroid glands or enlargement of the gland(s).
Other tests may be ordered to check for complications of hyperparathyroidism. These tests may include:
- A blood test to check your vitamin D level. It’s common to have a low vitamin D level if you have hyperparathyroidism.
- A bone density test to check for bone loss.
- An ultrasound or other imaging test of your kidneys to check for kidney stones.
- A 24-hour urine collection test to measure the amount of calcium and other chemicals in your urine to help determine the cause of your hyperparathyroidism.
- Blood tests to check how well your kidneys are working.
Management and Treatment
How is hyperparathyroidism treated?
If you have mild hyperparathyroidism (no symptoms, blood calcium levels only slightly elevated), your healthcare provider may not choose to treat it right away. Instead, your provider will monitor your blood calcium levels (every six months), blood pressure (every six months), kidney function (every year), and bone density (every one to three years).
If your healthcare provider believes your hyperparathyroidism doesn’t need immediate treatment, be sure to:
- Drink more water.
- Keep active and get more exercise to keep your bones strong.
- Don’t take thiazide diuretics or lithium because these drugs can increase the level of calcium in your blood.
- Ask your provider if you need to take a vitamin D supplement if your vitamin D level is low.
If you have more severe hyperparathyroidism symptoms or have an enlarged parathyroid gland (or glands) or a growth on your parathyroid gland, your provider may recommend surgery to remove the overactive gland(s). Surgery by an experienced surgeon can cure hyperparathyroidism in about 95% of cases.
Cinacalcet (Sensipar®) has been approved by the Food and Drug Administration for the treatment of secondary hyperparathyroidism. The drug works by signaling the parathyroid glands to produce less PTH. Although cinacalcet is intended for secondary hyperparathyroidism, some healthcare providers prescribe it for primary hyperparathyroidism.
Another medication type that is sometimes prescribed is bisphosphonates. These drugs help prevent loss of calcium from bones, which reduces the risk of fracture and osteoporosis. Examples of bisphosphonates include etidronate (Didronel®), alendronate (Fosamax®), zoledronic acid (Zometa®) and ibandronate (Boniva®).
If you're a woman and you’ve already gone through menopause and have signs of osteoporosis, your provider may prescribe hormone replacement therapy (HRT). HRT may help your bones retain calcium.
Can hyperparathyroidism be prevented?
No. Hyperparathyroidism can’t be prevented.
Outlook / Prognosis
What can I expect if I have hyperparathyroidism?
Surgery will cure nearly all cases of hyperparathyroidism. If you have surgery, your provider may want to check your calcium and PTH levels six weeks after surgery, and then on a yearly basis. You may also have a bone density test every year as well.
If you have mild symptoms and do not need surgery right now, your provider will carefully monitor your health and order blood tests to check your calcium and PTH levels. He or she will also order tests to watch for bone loss and other tests as needed.