The most common parathyroid disease is one (or more) of the four parathyroid glands grows into a tumor. This tumor is usually non-malignant but it does a great deal of damage to the body. When the tumor is formed on the parathyroid gland, it secretes more parathyroid hormone (PTH) than it should. The increase in PTH circulates in the blood and takes calcium out of the bones and into the blood.
Too much calcium causes symptoms that affect your brain, your nervous system, your bones, your muscles (including your heart), your kidneys, and your intestinal function. Parathyroid tumors are associated with kidney stones and osteoporosis. There are so many other problems that a tumor of the parathyroid can cause including uncontrolled hypertension, spasm of the veins and arteries, heart racing, depression, dehydration, and many others.