Parathyroid disorders involve unusual activity of the parathyroid glands, which are tiny glands found near the thyroid gland in the neck. The parathyroid glands make parathyroid hormone (PTH), which regulates the level of calcium in the body. Parathyroid disorders are marked by either hyperparathyroidism (overactivity) or hypoparathyroidism (underactivity).

Disorders of the parathyroid glands are likely to cause changes in the calcium content of the blood. A disruption of parathyroid function can affect the rest of the body by interfering with muscle contractions, nerve communications, and the growth and maintenance of bones.

Hyperparathyroidism, marked by excessive PTH, can draw calcium from the bones into the bloodstream and urine. People with this condition may develop osteoporosis, fractures, kidney stones, high blood pressure or other complications. The leading cause of hyperparathyroidism is noncancerous tumors. Other factors include chronic kidney failure and certain medications.

Hypoparathyroidism is characterized by insufficient PTH. This causes calcium levels in the blood to stay low and may impede nerve and muscle function. Hypoparathyroidism is rare and is most often caused by surgery or other trauma to the neck.

Most patients with parathyroid disorders are diagnosed before symptoms occur. Blood tests performed for other reasons may show abnormal levels of PTH and other markers of parathyroid disorders, such as abnormal levels of certain minerals. Urine tests, imaging tests and electrocardiogram are among the methods used to determine the severity of a patient’s parathyroid disorder and whether there are any complications.

Treating parathyroid disorders depends on whether the patient is experiencing hyper- or hypoparathyroidism, as well as whether symptoms have appeared. Treatments may include lifestyle changes, medication (e.g., vitamin and mineral supplements) or surgery.