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.

Having enough calcium in your body is important for healthy bones and teeth, and for muscle and nerve activity, including your heartbeat. But, having too much calcium can weaken your bones, cause kidney stones and in some cases, can be life threatening.  

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 hypercalcemia 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, then your doctor will monitor your condition on an ongoing basis. This will involve having blood tests every six months to check your calcium levels and kidneys. 

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.

An extremely high calcium levels is a medical emergency and requires hospitalisation. 


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, United States
Hypercalcaemia Patient Info, UK, 2017
Hypercalcaemia and hypercalciuria New Zealand Formulary, 2017

Credits: Health Navigator Editorial Team. Last reviewed: 14 Aug 2017