Parathyroid Disorders

Parathyroid disorders lead to abnormal levels of calcium in the blood that can cause brittle bones, kidney stones, fatigue, weakness, and other problems.

At the University of Michigan, our experts are focused on making an accurate diagnosis through comprehensive testing and providing the best therapy options for each patient.

What are the Parathyroid Glands?

Illustration showing rear view of thyroid and parathyroid glands

There are typically four parathyroid glands located near the thyroid gland. Each parathyroid gland is normally about the size of a grain of rice (about 3-5 millimeters in diameter and 30 - 60 milligrams in weight). Although the thyroid and parathyroid glands are physically near each other and are both part of your body's endocrine system, their functions are unrelated. Parathyroid glands release parathyroid hormone (PTH) which controls the calcium levels in the blood stream. Other areas of the body, especially the bones, kidneys and small intestine, respond to PTH by increasing calcium levels in the blood. Calcium is very important for our bodies, especially for muscle and nerve function.

About Parathyroid Disorders

As a rule, if the calcium level in the blood is low, the parathyroid glands sense this and release PTH. PTH then causes release of calcium from the bones into the bloodstream, increases vitamin D production from the kidney which ultimately increases absorption of calcium from the intestines. If the calcium level is too high, then PTH secretion should decrease to a very low level. 

Hyperparathyroidism exists when the parathyroid glands produce too much parathyroid hormone (PTH). This may be due to multiple reasons, and the reason helps determine the appropriate type of treatment. Sometimes treatment is as simple as replacing vitamin D when the parathyroid gland is responding appropriately to a problem elsewhere in the body. In other cases, there is an issue with the gland itself and surgery is required. Excess parathyroid hormone can lead to negative effects on the body such as osteoporosis which can lead to fractures, kidney stones, decreased kidney function, heart disease, pancreatitis, increased acid secretion in the stomach and ulcers. Many patients experience symptoms of fatigue, depression, anxiety, difficulty concentrating, difficulty with their memory, insomnia, generalized muscle aches and pains, frequent urination (especially at night), and constipation. Because these symptoms may be related to many other disorders, it is never known until after treatment whether or not these will improve.

The opposite problem, hypoparathyroidism, occurs when the parathyroid glands do not produce enough PTH. This leads to a low blood calcium level and can adversely affect muscle, nerve and other functions.

Diagnosis of Parathyroid Disorders

We diagnose parathyroid disorders through comprehensive testing that starts with a complete history and physical exam. Diagnosis of the type of hyperparathyroidism is based on blood work and other types of laboratory testing. Imaging tests are not used to diagnose parathyroid disorders, but may be ordered once the presence of a parathyroid disorder has been confirmed by lab tests.