The parathyroid glands are four glands at the front and base of the neck at
the 4 corners of the thyroid gland. These glands produce the parathyroid hormone
that regulates the calcium, phosphorus, and magnesium balance within the blood
as well as normal bone mineralization.
Excessive production of this hormone caused by increased activity of these
glands is known as hyperparathyroidism. When this occurs in response to low
blood calcium caused by another condition, the condition is called secondary
hyperparathyroidism. This is seen when vitamin D levels are low or when calcium
is not absorbed from the intestines. Correcting the calcium level and the
underlying problem will bring the parathyroid levels in the normal range.