Hypercalcemia (PDQ®)

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, a core part of our mission is to educate patients and the community about cancer. The following summary is trusted information from the NCI.

General Information About Hypercalcemia

Hypercalcemia is too much calcium in the blood.

Calcium is one of the most important minerals in the body. Most calcium is in the bones, but some is in the blood. Calcium works in the body in the following ways:

  • Makes bones and teeth strong.
  • Helps the heart, muscles, and nerves work.
  • Helps blood clot.

The amount of calcium in the blood is normally controlled by hormones, the kidneys, and bone.


Parathyroid hormone and calcitrol, are hormones that help balance the calcium level in the body.

  • Parathyroid hormone helps calcium enter the bloodstream from the kidneys and bone.
  • Calcitrol is a form of vitamin D. It helps the intestines absorb calcium.


Normal, healthy kidneys help the body keep the amount of calcium it needs. The kidneys can remove large amounts of calcium from the blood and pass the extra calcium into the urine.


Most of the calcium in the body is in bone, but bone has only a small role in keeping the balance of calcium in the body.

Hypercalcemia (too much calcium in the blood) is a very serious problem in cancer patients.

When calcium is out of balance, the whole body is affected. If hypercalcemia is not treated, it will get worse and can lead to a coma and death. Early diagnosis and treatment are very important and can be lifesaving and may help you continue your cancer treatment and improve your quality of life.

Hypercalcemia (too much calcium in the blood) is the most common life-threatening complication of cancer occurring in 10% to 20% of adults and rarely in children. Hypercalcemia occurs most often in patients with:

A physical exam and lab tests are used to diagnose hypercalcemia.

The symptoms of hypercalcemia may occur slowly and may look like other illnesses, making it hard to diagnose. Early diagnosis and treatment may improve symptoms in a few days.

The following tests and procedures may be used:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
  • Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a person's mental status, coordination, and ability to walk normally, and how well the muscles, senses, and reflexes work. This may also be called a neuro exam or a neurologic exam.
  • Electrocardiogram (EKG): A recording of the heart's electrical activity to evaluate its rate and rhythm. A number of small pads (electrodes) are placed on the patient's chest, arms, and legs, and are connected by wires to the EKG machine. Heart activity is then recorded as a line graph on paper. Electrical activity that is faster or slower than normal may be a sign of heart disease or damage.
  • Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as calcium, hormones, vitamin D, phosphate, and magnesium, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of one or more of these substances can be a sign of hypercalcemia.
  • Kidney function test: A test in which blood or urine samples are checked for the amounts of certain substances released by the kidneys. A higher or lower than normal amount of a substance can be a sign that the kidneys are not working the way they should. This is also called a renal function test.
  • Urinalysis: A test to check the color of urine and its contents, such as sugar, protein, red blood cells, and white blood cells.

Symptoms of Hypercalcemia

Certain types of cancer and types of treatment may cause symptoms of hypercalcemia.

Some cancer cells cause the kidneys to return calcium to the blood after filtering it, instead of passing the extra calcium out of the body in urine. The kidneys keep making urine as they try to get rid of the extra calcium, and this causes the body to be dehydrated (not enough fluid). Dehydration can lead to the following:

Cancer patients are often too tired and weak to be as active as usual. Being inactive can increase calcium in the blood because bones release calcium when they are not being used. Also, some blood cancers make substances that cause bone to break down and release calcium into the blood.

Certain types of biologic therapy used for cancer treatment can also cause hypercalcemia. These therapies include the following:

Hormone therapy can also increase the amount of calcium in the blood.

Different patients may have different symptoms.

Hypercalcemia symptoms may differ between patients. They can appear slowly over time and may look like symptoms of cancer and other diseases. The most common symptoms of hypercalcemia include the following:

  • Feeling tired.
  • Trouble thinking clearly.
  • Loss of appetite.
  • Pain.
  • Frequent urination.
  • Increased thirst.
  • Constipation.
  • Nausea.
  • Vomiting.

Hypercalcemia symptoms also depend on the organs that are affected.

Hypercalcemia can affect many organs of the body and symptoms depend on which organs are affected.

Neurologic symptoms

Calcium plays a major role in the way the central nervous system (the brain and spinal cord) works. Nervous system symptoms of hypercalcemia include the following:

  • Weakness.
  • Loss of reflexes.
  • Headaches, which can become worse by vomiting and dehydration.
  • Coma.
  • Mental problems, such as:

Sometimes mental problems need treatment separate from the treatment for hypercalcemia.

Heart symptoms

Hypercalcemia affects normal heart rhythms. It can also make the heart more sensitive to certain heart medicines (such as digoxin). Calcium levels that are higher than normal can cause irregular heartbeats or a heart attack.

Gastrointestinal symptoms

Increased stomach acid often occurs with hypercalcemia and may make the following symptoms worse:

  • Loss of appetite.
  • Nausea.
  • Vomiting.

Constipation may become worse if you are not drinking enough fluids.

Kidney symptoms

Hypercalcemia causes the kidneys to make too much urine. This loss of fluid may lead to dehydration, which causes the following symptoms:

  • Thirst.
  • Dry mouth.
  • Little or no sweating.
  • Dark yellow urine.
  • Poor elasticity (skin does not spring back in place when pulled up and released).

Patients with multiple myeloma often have kidney problems because of hypercalcemia. Kidney stones may form if hypercalcemia lasts a long time.

Bone symptoms

Hypercalcemia can be caused by cancer spreading to the bone or by bone loss. Bones may be painful or break.

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about hypercalcemia that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

Prevention of Hypercalcemia

Patients can learn to recognize early symptoms of hypercalcemia.

Hypercalcemia can be very serious and can cause death. It is important to learn how to recognize it early and manage it carefully. Patients at risk of hypercalcemia may be the first to notice its symptoms, such as fatigue. Ask your doctor if you are at risk for hypercalcemia and learn about the following:

  • Hypercalcemia symptoms.
  • Ways to prevent it.
  • What can make hypercalcemia worse.
  • When to call the doctor.

Patients can take steps to prevent hypercalcemia.

To prevent hypercalcemia, patients can do the following:

  • Drink the right amount of fluids.
  • Get enough salt in your diet.
  • Control nausea and vomiting.
  • Stay active by walking.
  • Control fever.
  • Stop taking drugs that can cause hypercalcemia or affect its treatment, when possible.

Hypercalcemia causes the body to absorb less calcium from food. However, changing the diet to decrease calcium will not lower the amount of calcium in the blood.

Treatment of Hypercalcemia

Treatment depends on how severe the hypercalcemia is.

Hypercalcemia may be mild, moderate, or severe. Because hypercalcemia can be caused by cancer itself, treatment for hypercalcemia will depend on how well the cancer treatment is working.

Severe hypercalcemia should be treated right away. Less severe hypercalcemia is treated based on the symptoms. The treatment is working if the symptoms of hypercalcemia disappear and the level of calcium in the blood decreases.

Treatment that decreases the amount of calcium in the blood usually:

  • Relieves symptoms.
  • Makes pain easier to control.
  • Improves quality of life.
  • Allows you to leave the hospital sooner (for patients with moderate to severe hypercalcemia).

After calcium levels return to normal, urine and blood samples will be checked often to make sure the treatment is still working.

Mild hypercalcemia.

Patients with mild hypercalcemia may not have any symptoms and usually do not need agressive treatment. If you have no symptoms of hypercalcemia and your cancer responds well to anticancer treatment, treatment for hypercalcemia may include:

If you have symptoms of hypercalcemia or your cancer is not expected to respond quickly to treatment, treatment for the hypercalcemia may include the following:

  • Drugs to lower the level of calcium in the blood.
  • Drugs to control nausea, vomiting, and fever.
  • Staying active.
  • Limiting the use of drugs that cause sleepiness.

Moderate to severe hypercalcemia.

Treatment for moderate to severe hypercalcemia includes the following:

  • Replace fluids.

    Replacing fluids is the first and most important step in treating moderate or severe hypercalcemia. This will not lower blood calcium to normal levels in all patients, but fluid replacement will improve symptoms such as confusion, nausea, and vomiting.

  • Drugs to control hypercalcemia.

    If cancer treatment cannot be started right away, then drugs to lower the calcium levels are used to control the hypercalcemia. The following drugs help stop the breakdown of bone and the release of calcium into the blood:

    Steroids and phosphates may also be used to treat hypercalcemia. Other drugs are being studied.
  • Begin dialysis treatment.

    Dialysis may be needed for patients with kidney failure.

Some patients may need medicine to manage confusion and other psychological symptoms.

Mental changes may take some time to get better, even after calcium levels return to normal. Usually, treatment of hypercalcemia will stop delirium, agitation, and mental changes, but some patients may need other medicines to treat these symptoms. (See the PDQ summary on Cognitive Disorders and Delirium for more information.)

Lethargy (feeling sluggish) is often a symptom of hypercalcemia. Family members (and sometimes medical staff) may think lethargy is depression until the actual cause is found. Most patients with lethargy will show little energy or interest in life. However, patients with lethargy will not have symptoms of depression (such as hopelessness, helplessness, guilt, worthlessness, or thoughts of suicide). It is important to know the difference between depression and lethargy so that the right treatment is given.

The decision to treat hypercalcemia depends on the treatment goals of the patient.

Hypercalcemia can make it hard to think clearly. Your choices about cancer care and treatment should be made when you are clearly able to decide for yourself. Untreated hypercalcemia will get worse and cause loss of consciousness and coma. Some patients who have advanced terminal cancer and are no longer getting treatment for the cancer may choose not to be treated for hypercalcemia.

Supportive Care for Hypercalcemia

Supportive care can comfort patients who are terminally ill.

When the cancer can no longer be treated, supportive care for hypercalcemia may include the following:

Supportive care can also help the family.

Supportive care can also comfort family members who may become upset by the changes hypercalcemia causes in their loved one's thinking and behavior.

Patients and caregivers should learn the signs of hypercalcemia.

Hypercalcemia can affect your quality of life and be life threatening if not treated right away. You and your caregiver should learn the symptoms to look for and report them to your doctor as soon as they occur. Staying active and drinking plenty of fluids will help prevent hypercalcemia. See the Symptoms of Hypercalcemia section for hypercalcemia symptoms.

Current Clinical Trials

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about hypercalcemia of malignancy that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

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