Parathyroid disease affects the parathyroids, four pea-sized glands located in the neck near the thyroid. The glands produce parathyroid hormone (PTH). PTH helps maintain the correct balance of calcium in the body. Normally, the glands release just enough PTH to keep calcium levels normal. Disease upsets this delicate balance.
There are three types of parathyroid disease: hyperparathyroidism, parathyroid cancer and hypoparathyroidism.
Hyperparathyroidism (HPT) is the most common type of parathyroid disease. In HPT, one or more glands are overactive. As a result, the glands make too much PTH. This may result in too much calcium in the blood—a condition called hypercalcemia. Usually, a benign tumor on the gland causes HPT.
Hypercalcemia can cause serious problems, including:
- kidney stones
- heart disease
- high blood pressure
Most people with primary HPT have no symptoms. Some people experience mild symptoms, such as:
- muscle weakness
- increased need for sleep
- aches and pains in the joints and bones
Symptoms for people with more severe disease may include:
- loss of appetite
- confusion or impaired thinking and memory
- increased thirst and urination
In rare cases, two or more of the glands are overactive. This is called hyperplasia.
HPT is most often diagnosed in people between the ages of 50 and 60. Women are affected about three times as often as men. Some people have HPT due to a rare genetic disorder called familial hypocalciuric hypercalcemia. This condition is typically benign and does not require treatment.
In some cases, a problem such as kidney failure causes the parathyroid glands to become overactive. This is called secondary HPT.
Parathyroid cancer can cause HPT. This very rare disease usually strikes people in their 50s. It often returns, or recurs, at the original site after treatment. Recurrence can be slowed by controlling the level of calcium in the blood.
Early detection is key to survival. Hypercalcemia and its associated complications often pose a greater threat to your health than the cancer itself.
Hypoparathyroidism means the body does not make enough PTH. As a result, the level of calcium in the blood is too low. The condition is usually caused by neck surgery or damage to the parathyroids. It can also happen from autoimmune attacks on the glands.
Hypoparathyroidism increases the risk of:
- Addison’s disease, a disorder that occurs when the adrenal glands don’t make enough hormones. This risk is associated only with autoimmune-related hypoparathyroidism.
- Parkinson’s disease, a progressive disorder that affects the brain and causes abnormal movements and other symptoms. See the Movement Disorders page for more information.
- Pernicious anemia, a condition in which the body cannot make enough red blood cells due to a lack of vitamin B-12. People with this disorder are unable to absorb enough B-12 from food. This risk is associated only with autoimmune-related hypoparathyroidism.
How is parathyroid disease diagnosed and evaluated?
Your doctor may diagnose parathyroid disease by testing the levels of calcium and PTH in your blood.
After diagnosis, the following tests may be done to assess complications:
Bone densitometry (DEXA, DXA): Bone densitometry, also called DEXA or DXA, uses a very small dose of ionizing radiation to produce pictures of the inside of the body (usually the lower spine and hips) to measure bone loss. DXA is simple, quick and noninvasive.
Ultrasound: Ultrasound imaging uses sound waves to produce pictures of the inside of the body. Ultrasound is safe, noninvasive, and does not use radiation.
Computed tomography (CT) – body: CT scans use a combination of x rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of contrast material. CT scans require the person to lie on a table that slides into a tunnel-shaped device where the x rays are taken. The procedure is often performed in an outpatient center, and the images are interpreted by a radiologist; anesthesia is not needed.
Magnetic resonance imaging – body: Body MRI uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the inside of your body.
25-hydroxy-vitamin D blood test: people with primary HPT commonly lack vitamin D. This test helps your doctor monitor vitamin D levels in your blood and determine if you need supplements.
How is parathyroid disease treated?
Treatment options include surgery, medication, dietary supplements and monitoring.
Surgical removal of overactive parathyroid glands is highly effective in most patients. Surgery can benefit nearly everyone with primary HPT who exhibit symptoms. Those without symptoms but who meet guidelines for surgery also may benefit. Surgical removal of diseased parathyroids can lead to higher bone density, fewer fractures and a reduced chance of kidney stone formation.
Prior to surgery, doctors may use one or more of the following tests to locate the diseased gland(s):
- Four-dimensional computed tomography (4DCT): Parathyroid 4DCT provides a more detailed view than conventional CT. This is made possible by administering contrast material at a specific rate and time. 4DCT is particularly useful when other imaging studies fail to show the abnormal gland.
- Ultrasound: This test may be used to find benign tumors on one or more of the glands.