What to Know About Hypercalcemia

Medically Reviewed by Jennifer Robinson, MD on September 23, 2023
5 min read

Calcium is an important nutrient that your body needs to grow strong bones and keep you healthy. High blood calcium often does not cause any symptoms. But over time, very high calcium levels can cause symptoms and lead to health problems.

Hypercalcemia, or high blood calcium, happens when another condition causes high levels of calcium to build up in your blood. The extra calcium can cause several health problems, such as weak bones, kidney stones, and heart and brain problems.

Normally, your body controls blood calcium through several hormones. But more than 25 diseases and conditions, such as cancer, kidney problems, medication problems, or even severe dehydration, can cause hypercalcemia

The main causes of high calcium include:

Hyperparathyroidism. It’s a condition in which four pea-sized glands (parathyroid) at the back of your thyroid gland in your throat start to produce too much parathyroid hormone (PTH), regardless of the level of calcium. This leads to an abnormal increase in calcium levels in your blood. Hyperparathyroidism accounts for nearly 90% of hypercalcemia cases. About 100,000 people get hyperparathyroidism in the U.S. every year. Postmenopausal women are at the highest risk.

Medications. Some drugs and dietary supplements can cause an increase in calcium levels in your blood. These include:

Cancer. Certain types of cancers that affect your blood, lungs, or breasts can also cause hypercalcemia. This can happen because of bone metastases or hormones that some types of cancer produce.

Less common causes of hypercalcemia can include:

It’s also possible to inherit a genetic form of hypercalcemia. Familial hypocalciuric hypercalcemia can cause you to have faulty calcium receptors (proteins that help regulate calcium levels) and lead to high levels of calcium in your blood.

If you have mild hypercalcemia, you may not notice signs or symptoms. But if you have a severe case, it can affect different parts of your body.

Symptoms can include:

If you notice any of the signs or symptoms, tell your doctor about it.

Having too much calcium in your blood can cause other health complications, such as:

Osteoporosis. Hyperparathyroidism may cause your bones to release large amounts of calcium into your blood, which can make them thin and weak. This is called osteoporosis. It can increase your chances for bone breaks and spinal problems.

Kidney stones. If there’s too much calcium in your urine, it can form small, painful stones in your kidney. Passing the stone can be very painful.

Kidney failure. Hypercalcemia can affect the way your kidneys work and make it hard for them to get rid of toxins and cleanse your blood.

Problems with brain function. High calcium levels in your blood can cause nervous system problems and hurt your thinking skills. It can cause confusion, dementia, and, in severe cases, coma.

Heart problems. Abnormally high calcium levels can cause faulty electrical pulses in your heart, which may lead to an abnormal or irregular heartbeat (arrhythmia).

As there are few or no noticeable signs or symptoms of hypercalcemia, you may not know your blood calcium levels are high until your doctor checks you out.

Your doctor may order a blood test to check for hypercalcemia. The blood test can also tell if your parathyroid glands are secreting high levels of PTH. This can help the doctor diagnose you with hyperparathyroidism, which is usually the cause of hypercalcemia.

Other tests to check for hyperparathyroidism include:

If your doctor suspects that your hypercalcemia stems from another condition, like cancer, they may order imaging tests like an X-ray, MRI, or CT scan to check your lungs and bones.

Your doctor will come up with a treatment plan based on how severe your hypercalcemia is. If it’s mild, your doctor may choose to closely monitor your calcium levels and recommend you:

  • Drink lots of water.
  • Switch or stop diuretic medications.
  • Stop taking calcium-rich antacid tablets.
  • Stop calcium supplements.

If you have severe hypercalcemia, your treatment options may include medications or surgery.

Medications can include:

  • Cinacalcet (Sensipar) for hypercalcemia
  • Calcitonin, a hormone from salmon that helps regulate calcium levels
  • Prednisone, a steroid that can lower high calcium levels caused by too much vitamin D
  • Bisphosphonates to treat osteoporosis caused by cancer
  • Denosumab (Prolia, Xgeva), an alternative to bisphosphonates for cancer-related hypercalcemia

If your hypercalcemia came from overactive parathyroid glands, your doctor may recommend surgery to remove the affected gland.

If you have hypercalcemia, your outlook will depend on how severe your condition is and what’s causing it. If it’s mild, you may not have other health complications. You can follow your doctor’s recommendations and take the steps needed to manage and monitor your calcium levels.

If it’s severe, depending on what’s causing your hypercalcemia, your doctor will come up with a treatment plan to suit your health and medical circumstances. If cancer is causing it, you may have to go to the hospital for routine IV fluids and other treatments.

While it’s not possible to prevent hypercalcemia if it stems from another medical condition such as cancer, you can take some steps to manage your blood calcium levels.

You can:

  • Tell your doctor about any family history of hyperparathyroidism, kidney stones, or high blood calcium. This can help them monitor and catch your hypercalcemia early.
  • Avoid taking calcium-rich supplements or antacids without consulting your doctor first.
  • Check with your doctor before taking any dietary supplements, vitamins, or minerals.