Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be

talking to you about hyperparathiridism. If you want to follow along with written notes on this topic,

you can follow along at zero tofinals.com slash hyperparathiridism or in the endocrinology section of the zero definals medicine book.

Let's get straight into it. Let's start with some basic anatomy and physiology. There's four

parathyroid glands and these four parathyroid glands are situated in the four corners of the thyroid gland.

And the parathyroid glands are situated in the four corners of the thyroid gland. And the parathyroid glands,

specifically the chief cells in the glands, produce parathyroid hormone, and they produce it in response to hypo-calcemia, or low-blood calcium. And the parathyroid hormone acts to raise the blood

calcium.

And it does this by doing four things.

Firstly, it increases the osteoclasts activity in the bones.

I remember that osteoclasts are responsible for reabsorbing calcium from the bones.

It increases the calcium absorption from the gut, it increases calcium absorption from the kidneys,

and it increases the activity of vitamin D.

Specifically, parathyroid hormone acts to convert

vitamin D into its active forms,

and vitamin D acts to increase calcium absorption from the intestines.

So vitamin D and parathyroid hormone act together to raise the blood calcium level.

There's three types of hyperparathyroidism, primary, secondary and tertiary, and it's useful to get

your head around these three.

Primary hyperparathyroidism is caused by uncontrolled parathyroid hormone

produced directly by a tumour of the parathyroid glands.

And this leads to hypercalcemia, or an abnormally high level of calcium in the blood,

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