Parathyroid Glands

The parathyroid glands are four pea-sized glands located in the neck. They are part of the endocrine system. (Read about "The Endocrine System") They are found at the base of the neck near the thyroid gland. (Read about "Thyroid") Although the names sound similar, the parathyroids and the thyroid are completely separate glands.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says the parathyroid glands secrete parathyroid hormone (PTH), a substance that helps maintain the correct balance of calcium (Read about "Calcium") and phosphorous in the body. Calcium and phosphorus are important for many bodily processes, including the maintenance of healthy bones and teeth. (Read about "Calcium and Osteoporosis") PTH regulates the release of calcium from bone, absorption of calcium in the intestine and excretion of calcium in the urine. (Read about "The Urinary System")

When the amount of calcium in the blood falls too low, the parathyroid glands should secrete just enough PTH to restore the balance.

If the glands secrete too much hormone, as in hyperparathyroidism, the balance is disrupted: blood calcium rises. If the glands secrete too little, hypoparathyroidism can result. Hypoparathyroidism is much less common.

Below, you'll find information on hyperparathyroidism, hypoparathyroidism and parathyroid cancer.

Hyperparathyroidism

Hyperparathyroidism is when the parathyroids secrete too much parathyroid hormone (PTH). The excess PTH causes blood calcium levels to rise. This condition of excessive calcium in the blood is called hypercalcemia. (Read about "Hypercalcemia") Hypercalcemia can lead to bone pain, bone loss and other problems. (Read about "Skeletal System")

In the United States, NIDDK says about 100,000 people develop the disorder each year. Women outnumber men two to one, and risk increases with age.

Hyperparathyroidism can develop in two ways:

• Primary hyperparathyroidism is a disorder of the parathyroid glands. Most people with this disorder have one or more enlarged, overactive parathyroid glands that secrete too much parathyroid hormone.
• In secondary hyperparathyroidism, a problem, such as kidney failure, makes the body resistant to the action of parathyroid hormone. (Read about "Kidney Disease")

According to NIDDK, in 85 percent of people with primary hyperparathyroidism, a benign tumor (adenoma) has formed on one of the parathyroid glands, causing it to become overactive. In most other cases, the excess hormone comes from two or more enlarged parathyroid glands, a condition called hyperplasia. Very rarely, says NIDDK, hyperparathyroidism is caused by cancer of a parathyroid gland (see below).

Excess PTH can cause a number of problems. For example, the bones may lose calcium, and get thinner or more porous. (Read about "Osteoporosis") In addition, the levels of calcium may increase in the urinary system; that can increase the possibility of kidney stones. (Read about "Kidney Stones")

Symptoms of hyperparathyroidism range from none at all to nausea, vomiting and fatigue. Hyperparathyroidism is diagnosed when tests show that blood levels of calcium and parathyroid hormone are too high. Due to the high risk of bone loss, a bone density scan is often used. (Read about "DEXA Scan - Dual Energy X-Ray Absorptiometry/Densitometry") Urine tests and abdominal scans can also be used to check for kidney stones. (Read about "Ultrasound Imaging" "CT Scan - Computerized Tomography")

Surgery to remove the enlarged gland (or glands) is the main treatment for the disorder, according to NIDDK, and cures it in 95 percent of cases when performed by an experienced surgeon. Surgery does carry the risk of damage to the nerves controlling the vocal cords, which can affect speech. There is also the chance that too much parathyroid tissue will be removed, resulting in hypoparathyroidism (see below). In some cases, drugs may be used to turn off secretion of PTH. NIDDK says there are also cases in which treatment is not needed. Patients who are symptom free, whose blood calcium is only slightly elevated and whose kidneys and bones are normal may wish to talk to their doctor about long-term monitoring.

Hypoparathyroidism

Hypoparathyroidism is considered a rare disorder. Hypoparathyroidism is a disorder that causes lower than normal levels of calcium in the blood due to insufficient levels of parathyroid hormone (PTH). Phosphorus metabolism is also affected.

Symptoms can include:

• weakness and muscle cramps
• tingling, burning and numbness of the hands
• excessive nervousness and/or headaches
• loss of memory
• spasms of the face, wrists and feet

According to the Hypoparathyroidism Association, this condition can be inherited, associated with other disorders, or it may result from neck surgery. Treatment centers on restoring calcium and vitamin D to the body. (Read about "Vitamins & Minerals")

Parathyroid Cancer

Cancer of the parathyroid is called very rare by the National Cancer Institute (NCI). Symptoms for parathyroid cancer include the following according to NCI:

• bone pain
• a lump in the neck
• upper back pain
• weakness
• difficult speech
• vomiting

Problems with the parathyroid are common and very seldom involve cancer, according to NCI. A doctor should be consulted about any symptoms. Diagnostic tests include physical exam, the use of a thin, lighted tube called an endoscope to examine areas inside the body, x-rays, CT scans, MRI, Pet scans and/or biopsy. (Read about "Endoscopy" "X-rays" "CT Scan - Computerized Tomography" "MRI - Magnetic Resonance Imaging" "PET - Positron Emission Tomography" "Biopsy")

If cancer is present, the doctor will want to learn the stage (or extent) of disease. Staging is a careful attempt to find out whether the cancer has spread and, if so, to which parts of the body. Staging may involve an examination under anesthesia (Read about "Anesthesia"), x-rays and other imaging procedures, and laboratory tests. (Read about "Laboratory Testing") Treatment options include surgery, radiation, chemotherapy and biological therapy. (Read about "Radiation Therapy" "Cancer Treatments") NCI says surgery is the most common treatment. Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or stop them from growing. Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells.