High Calcium Levels or Hypercalcemia

Approved by the Cancer.Net Editorial Board, 01/2020

Calcium is a mineral found in different places in the body, including your blood. When you have more calcium in your blood than normal, doctors call it "hypercalcemia." It is a serious condition. Up to 30% of all people with cancer will develop a high calcium level as a side effect.

A high calcium level can be treated, and it is important to talk with your doctor if you experience any symptoms. Left untreated, a high calcium level can cause severe problems, like kidney failure, and it can even be life-threatening.

Treatment for side effects is an important part of cancer care. This type of treatment is called supportive care or palliative care. Talk with your health care team about any symptoms you have, including new symptoms or changes. This helps them find side effects like a high calcium level as early as possible.

About calcium in your body

Everybody needs calcium for many body functions. It helps form bones and teeth, and it also helps your muscles, nerves, and brain work correctly. Most of the calcium in your body is in your bones. Normally, your blood contains only a small amount. When you are healthy, your body controls the level of calcium in your blood.

Cancer can cause a high calcium level in the blood in several ways. High calcium levels due to cancer are not caused by too much calcium in your diet. Eating fewer dairy products and other high-calcium foods will not lower high blood calcium levels.

Cancers that more commonly cause high calcium levels in your blood include:

  • Lung cancer

  • Head and neck cancers

  • Multiple myeloma

  • Leukemia

  • Kidney cancer

  • Breast cancer

  • Gastrointestinal (digestive system) cancers

Learn more about specific types of cancer.

What are the symptoms of a high calcium level?

Symptoms of a high calcium level often develop slowly. You may not notice them at first, because they can feel like the symptoms of cancer or treatment. Or, you may not have any symptoms.

The severity of your symptoms does not depend on how high your calcium level is. Different people have different reactions. Older people usually have more symptoms than younger people.

If you do have symptoms, they may includes:

  • Loss of appetite

  • Nausea and vomiting

  • Constipation and abdominal (belly) pain

  • The need to drink more fluids and urinate more

  • Tiredness, weakness, or muscle pain

  • Confusion, disorientation, and difficulty thinking

  • Headaches

  • Depression

Serious symptoms can include:

  • Seizure

  • Irregular heartbeat

  • Heart attack

  • Loss of consciousness

  • Coma

You and your family should know these serious symptoms. Ask your doctor what you should watch for and when to get treatment.

How are high calcium levels diagnosed and how are they managed?

Your doctor can do a blood test to learn if you have a high calcium level. You may also have blood tests to check how well your kidneys are working. Your doctor will treat a high calcium level if you have it. The treatment depends on how severe the condition is.

Mild hypercalcemia

People who have no symptoms receive extra fluids, usually given through a vein. This will help your kidneys remove extra calcium from your blood.

Moderate or severe hypercalcemia

This can be treated by:

  • Continuing cancer treatment.

  • Replacing fluids lost through vomiting and urination.

  • Taking medication to stop bone from breaking down. You may be prescribed a bisphosphonate, such as zoledronic acid (Zometa), pamidronate (Aredia), or ibandronate (Boniva), or denosumab (Prolia, Xgeva). Talk with your doctor about the risks and benefits of taking such medications.

  • Taking medicine called steroids. These can help stop bone from breaking down. They also help your bones take more calcium from your food. Steroids can also raise your risk of bone loss over time. Talk with your doctor about the risks and benefits of taking steroids.

  • Taking a hormone called calcitonin. This hormone functions by reducing calcium release from your bones and increase calcium secretion from your kidneys.

  • Using dialysis if you haves kidney failure. Dialysis is a machine-based process that cleans your blood when your kidneys are not working properly.

Treating a high calcium level helps relieve your symptoms. When you feel better, it is easier to continue your cancer treatment.

For people with advanced cancer, high calcium levels can occur when they are approaching the last weeks of life. In these cases, the health care team will discuss whether to treat hypercalcemia.

Can high calcium levels be prevented?

There are things you can do to help prevent high calcium levels. The following tips may help keep hypercalcemia from getting worse:

  • Drink fluids regularly.

  • Talk with your doctor about controlling your nausea and vomiting.

  • Walk and be active, which can help stop bone from breaking down.

  • Check with your doctor before taking any medication, including over-the-counter supplements. Some may make high calcium levels worse.

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