What is it?
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 oval, grain-of-rice-sized glands 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. Secondary hyperparathyroidism is a result of another disease that causes low levels of calcium in the body. Surgery is the most common treatment for hyperparathyroidism.
Hyperparathyroidism is often diagnosed before signs or symptoms of the disorder are apparent. When symptoms do occur, they are the result of damage or dysfunction in other organs or tissues due to high calcium levels circulating in the blood 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
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 as 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 you consume.
- 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, useable 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
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.
- 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 a combination of two imaging tests to locate the parathyroid gland or glands that are causing problems:
- 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.
- Sestamibi scan. Sestamibi is a specially designed radioactive compound that is absorbed by overactive parathyroid glands and can be detected on computerized tomography (CT) scans. A small dose of the compound is injected into your bloodstream before the imaging test is done.
How do you treat it?
Like any disease, even if there is no cure, there is almost always something you can do to manage it and take control. There are three main areas involved in the treatment of any disease:
How do you live with it?
Certain adjustments may be needed to get on with your life, and often, some simple tips and advice can go a long way to making these changes.
When you come to a Lynch's Pharmacy Clinic, we give you all the necessary information available to make your life more manageable and allow you to better live with your condition.