Raised calcium levels

Hypercalcaemia is when the calcium level in your blood is raised. Having excess calcium in your blood can weaken your bones, cause kidney stones and affect how your heart works.

Key points

  1. Having enough calcium in your body is important for healthy bones and teeth, and for muscle and nerve activity, including your heartbeat.
  2. But having too much calcium can weaken your bones, cause kidney stones and, in some cases, be life-threatening.
  3. Causes vary, but the most common one is overactive parathyroid glands producing too much of the hormone that controls the amount of calcium in your body.
  4. Symptoms are quite general so you often don't know you have this condition until it is picked up in a blood test.
  5. Treatment depends on the cause and how high your calcium levels are. It may involve monitoring, medication or surgery.

What causes hypercalcaemia?

There are many causes of raised calcium levels, the most common being overactive parathyroid glands, which secrete too much parathyroid hormone. This hormone helps control the amount of calcium in your body. When too much parathyroid hormone is secreted, your bones may lose calcium and the levels of calcium in your blood and urine rise. Read more about overactive parathyroid glands (also called hyperparathyroidism).

People with cancers such as lung cancer or breast cancer are at increased risk of having hypercalcaemia.  

Other less common causes include:

  • medicines such as diuretics (water tablets) or lithium 
  • too much calcium or vitamin D in the diet, usually as a result of taking supplements 
  • severe dehydration
  • kidney problems
  • other diseases such as tuberculosis and sarcoidosis 
  • being inactive, such as spending a lot of time sitting or lying in bed.

What are the symptoms of hypercalcaemia?

Most people with hypercalcaemia are not usually aware they have it. It may be picked up by your doctor in a routine blood test. The symptoms are quite general and non-specific.

Symptoms of hypercalcaemia
  • feeling thirsty, dry mouth
  • peeing (urinating) more than usual
  • increasing weakness, tiredness and feeling unwell
  • loss of appetite
  • feeling drowsy, sleepy and having problems concentrating 
  • constipation
  • stomach upset
  • nausea (feeling sick)
  • vomiting (being sick)
  • pain in the joints, bones or muscles

How is hypercalcaemia treated?

The treatment of hypercalcaemia depends on what is causing it and how severe it is. If the levels of calcium in your blood are only slightly high and you do not have any symptoms, your doctor will monitor your condition on an ongoing basis. This will involve having blood tests every 6 months to check your calcium levels and kidneys. Your doctor may advise you to:

  • drink more water each day to reduce the risk of kidney stones
  • not exceed the recommended dietary calcium intake ie, about 1000 mg per day
  • ensure you are getting enough vitamin D.

If you have extremely high calcium levels in your blood, you may need to be hospitalised. This is so a doctor can reduce your calcium levels and monitor you regularly.

If your hypercalcaemia is due to an overactive parathyroid gland, you may require surgery to remove the parathyroid gland. Read more about treatment options for hyperparathyroidism

For hypercalcaemia due to cancer, osteoporosis medicines called bisphosphonates are given by injection into your vein. If it is caused by high levels of vitamin D or sarcoidosis, then a short course of steroids such as prednisone may be given.

What questions should I ask my healthcare team about hypercalcaemia?
If you are diagnosed with hypercalcaemia, you may have lots of questions for your doctor, nurse, pharmacist or other healthcare professional. It’s okay to ask questions. Here are a few suggestions.
  • What is causing my hypercalcaemia?
  • How severe is my hypercalcaemia?
  • What are my treatment options?
  • What are the side effects of treatment?
  • What can I do to reduce the symptoms of hypercalcaemia?
  • How will having hypercalcaemia affect my everyday life?
  • Are there any foods I need to stop eating?

Learn more

The following links provide further information about hypercalcaemia. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Hypercalcemia Mayo Clinic, US
Hypercalcaemia Patient Info, UK
Hypercalcaemia and hypercalciuria NZ Formulary

Information for healthcare providers

Hypercalcaemia and hypercalciuria

Reviewed by

Dr Helen Kenealy is a geriatrician and general physician working at Counties Manukau DHB. She has a broad range of interests and has worked in a variety of settings including inpatient rehabilitation, orthgeriatrics and community geriatrics.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Helen Kenealy, geriatrician and general physician, Counties Manukau DHB Last reviewed: 10 Aug 2020