Hyperparathyroidism (overactive parathyroid glands) - FAQs

What are the parathyroid glands?

There are 4 parathyroid glands, each is normally the size of a lentil or split pea. They sit on the back of the thyroid gland (2 on each side) and release a hormone (parathyroid hormone, PTH) that regulates the level of calcium in the blood.

Why are they important?

Calcium is vital for strong bones, muscle and nerve function and many of the processes that go on within cells of the body. Over active parathyroids produce too much PTH – this weakens the bones, may cause multiple symptoms (tiredness, thirst, aches and pain, depression) and may cause kidney stones, osteoporosis, fractures and cardiovascular problems.

What causes the parathyroid glands to produce too much PTH?

In 90% of people a single enlarged gland is the cause and at present the cause in most people is unknown, although several genetic changes have been identified as possible triggers. Fortunately in more than 95% of patients, the disorder is curable with a straightforward surgical procedure.