Your parathyroid glands are four small glands in your neck that control levels of calcium and phosphate in your body. They do this by making a hormone called parathyroid hormone.

This hormone helps to control:

• how much calcium is absorbed from food
• how much calcium and phosphate are removed from the blood by the kidneys (in pee)
• how much calcium is released into the blood from the bones

Vitamin D also helps the body to absorb calcium from food.

If your parathyroid glands become overactive, they can make too much parathyroid hormone. The medical term for this is hyperparathyroidism.

Hyperparathyroidism can lead to:

• weak bones and muscles
• kidney stones
• tiredness
• tummy (abdominal) pain
• constipation (not pooing as often as usual or finding it harder to poo)

Hyperparathyroidism can occur for a number of reasons. When it’s the result of another disease (such as ADPKD), it’s known as ‘secondary hyperparathyroidism’.

Hyperparathyroidism is common in people with ADPKD who have kidney failure, especially if they’re on dialysis.

In people with kidney failure, the kidneys can’t activate vitamin D which is needed to absorb calcium from food. The parathyroid glands sense that calcium levels are low and make more parathyroid hormone to try to correct this. This doesn’t work because the gut still can’t absorb calcium well without activated vitamin D. The high level of parathyroid hormone causes too much calcium to be taken from the bones.

Failing kidneys also can’t remove enough phosphate from the blood.

A doctor can diagnose hyperparathyroidism using a blood test.

When hyperparathyroidism is caused by kidney disease, blood tests typically show:

• high levels of parathyroid hormone
• low or normal levels of calcium
• high levels of phosphate

Your doctor can also use blood tests to monitor your condition and see whether treatments help.

If you have hyperparathyroidism, your doctor may arrange a bone scan to check the strength of your bones. This scan is called a bone density X-ray or ‘DEXA’. It uses a special type of X-ray to measure how dense your bones are. This is to check whether you have weak bones and are at risk of bone fractures.

If your bones are weak, your doctor can prescribe bisphosphonates and other medicines to help.

Changes to your diet and medicines can help to correct your calcium and phosphate levels.

• If you’re on dialysis, a special dialysis fluid containing calcium can be used to boost your blood calcium levels. The dialysis machine can also remove excess phosphate from your blood.
• Medicines called calcitriol and vitamin D analogues improve calcium levels. Calcitriol is an active form of vitamin D and helps you to absorb calcium from your food.
• Medicines called calcimimetics (cinacalcet and etelcalcetide) can reduce levels of parathyroid hormone.
• A phosphate binder can reduce phosphate levels.
• Avoiding foods high in phosphate can help to reduce phosphate levels.

Foods high in phosphate include: milk and milk products, whole grains, dried beans and peas, nuts, seeds, meat, fish, offal (animal innards), cola, chocolate and some baking powders.

You’ll have regular blood tests to check that your calcium and phosphate levels are within a healthy range.

If these steps don’t work to control your calcium and phosphate levels, a surgeon may recommend surgery to remove your parathyroid glands (or part of them).

You’re unlikely to need your parathyroid glands removed if your kidneys are still working quite well. About 5–10 in every 100 people who have reached kidney failure need to have these glands removed.

People who have been on dialysis for a long time are most likely to need this surgery.

Having a kidney transplant doesn’t always reverse problems with the parathyroid glands. So, if you’ve had a transplant (or are waiting for one) and have hyperparathyroidism that isn’t getting better with medicines, you might need to have your parathyroid glands removed.

You’ll have a general anaesthetic for the operation, which takes about 1 hour. Your surgeon will make a cut in your neck to reach the glands. You’ll probably need to stay in hospital overnight, or possibly longer, if your calcium levels fall after surgery.

Removal of the parathyroid glands is generally low risk. As with any minor surgery, there is a small risk of bleeding and infection. We don’t have exact numbers on this, but your surgeon will explain risks before the operation.

Fewer than 1 in every 100 patients gets a swelling of blood under the skin of their neck that needs draining. This swelling is called a hematoma. It can make it harder to breathe, which is why drainage is important.

The operation can cause a change to your voice (for example, it being hoarse, croaky, or weak). This usually gets better within days to weeks. However, about 1 in every 100 people has a longer-term change and may need voice therapy or surgery.

Many people get ‘hungry bone syndrome’, which we explain below.

Your treatment team will monitor your calcium levels carefully after your parathyroid glands are removed.

You’ll need to take calcium tablets (usually in the form of calcium carbonate or calcium citrate) as well as calcitriol (active vitamin D). Your treatment team will adjust the doses of these depending on your blood test results.

After parathyroidectomy, your bones will soak up calcium from the blood to replenish their normal levels. If they do this too quickly, it can make calcium levels in the blood fall. This is called ‘hungry bone syndrome’. It’s important for this to be corrected as very low calcium levels in the blood can cause heart problems and seizures.

If you get ‘hungry bone syndrome’, you might need a drip (infusion) of calcium until your calcium levels balance. If you’re on dialysis, calcium can be given in the dialysis fluid.

It might take a few months and treatment adjustments to get this right, so you’ll have regular blood tests to check your calcium levels. You can then slowly change to taking calcium tablets and calcitriol.

• ADPKD progression (approaching kidney failure)
• Introduction to Dialysis

• Kidney Research UK has information on secondary hyperparathyroidism.
• The NHS has information on bone density scans (DEXA).
• North and East Hertfordshire NHS Trust has information on surgery to remove the parathyroid glands (parathyroidectomy).