Hypoparathyroidism

Definition:

A deficiency of parathyroid hormone.

Causes, incidence, and risk factors:

The parathyroid glands are located at the front and base of the neck around the thyroid gland. The glands produce parathyroid hormone, which regulates calcium, phosphorus, and magnesium balance within the blood and normal bone mineralization.

Without sufficient amounts of parathyroid hormone, the calcium level in the blood falls and produces symptoms and problems. Hypoparathyroidism may be caused by a genetic disorder; congenital absence of the parathyroid glands; accidental removal or injury of the parathyroid glands during surgery to remove the thyroid gland or other neck surgery; massive radiation to the thyroid gland; or magnesium deficiency.

Risk factors are recent thyroid or neck surgery, family history of parathyroid disorder, or history of certain autoimmune endocrine diseases such as Addison's disease. The incidence is 4 out of 100,000 people.