What causes high blood calcium?

The most common cause of high blood calcium is primary hyperparathyroidism, which results in overproduction of parathyroid hormone by the parathyroid glands. The parathyroid glands play a role in the body’s regulation of calcium levels in the blood. In most cases, the causes associated with primary hyperparathyroidism disease are not known.

You can also develop high blood calcium as a result of adrenal failure, too much calcium in your diet, genetic conditions that affect how your body processes calcium, anorexia, hyperthyroidism, kidney disease, reactions to some medications, certain types of tumors, and an excess of vitamin D.

Common causes of high blood calcium

High blood calcium may be caused by a wide variety of conditions and diseases including:

  • Adrenal failure
  • Anorexia
  • Certain medications, especially certain diuretics or lithium
  • Dehydration
  • Excess vitamin D
  • Hyperthyroidism
  • Kidney disease or failure
  • Primary hyperparathyroidism (overproduction of parathyroid hormone by the parathyroid glands)
  • Specific cancers, including some types of lung cancers
  • Vomiting associated with eating disorders such as bulimia

Rare causes of high blood calcium

High blood calcium can also be caused by less common conditions including:

  • Familial hypocalciuric hypercalcemia (condition in which insufficient calcium is excreted)
  • Overabundance of calcium in the diet
  • Rare cancers

Serious or life-threatening causes of high blood calcium

In some cases, high blood calcium may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These conditions include:

  • Acute kidney failure
  • Certain cancers such as some lung cancers and multiple myeloma

Questions for diagnosing the cause of high blood calcium

In meeting with you to diagnose your condition, your health care provider will ask a series of questions related to your high blood calcium including:

  • When did you first notice your symptoms?
  • Do you have any other symptoms?
  • Where do you feel your symptoms?
  • What medications are you taking?
  • What does your typical daily diet include?
  • Does anything improve your symptoms?
  • Does anything you do cause your symptoms to worsen?
  • Do you have any family history of high blood calcium?

What are the potential complications of high blood calcium?

Potential complications of high blood calcium vary in severity and depend upon the underlying cause. These complications can range from minimal to life-threatening. If your high blood calcium is due to a readily treatable condition, such as primary hyperparathyroidism, treatment is usually effective and your risk of potential complications is minimal. When high blood calcium is due to a serious disease, such as cancer, the potential complications from the disease itself can be severe.

Because any of a number of serious diseases may lie at the root of your high blood calcium, it is vitally important to seek medical treatment promptly to minimize risk of potential complications including:

  • Arrythmia (abnormal heart rhythm)
  • Bone fractures
  • Cognitive changes (problems concentrating, changes in behavior, and impaired memory)
  • Kidney failure
  • Kidney stones
  • Osteoporosis
  • Spread of cancer
  • Unconsciousness and coma


Hypercalcemia. PubMed Health. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001404/. Accessed May 25, 2011.

Hypercalcemia (PDQ). National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/supportivecare/hypercalcemia/Patient/page1. Accessed May 25, 2011.


What is high blood calcium?

High blood calcium (hypercalcemia) is a condition of too much calcium in your blood. You may become aware of high blood calcium through a laboratory test or you may experience one or more nonspecific symptoms, including abdominal pain, flank pain, frequent urination, muscle weakness, or mood changes.... Read more about high blood calciumintroduction


What other symptoms might occur with high blood calcium?

You may experience other symptoms with high blood calcium, and they vary depending on the underlying disease, disorder or condition.... Read more about high blood calciumsymptoms

Medical Reviewer: All content has been reviewed by board-certified physicians under the direction of Rich Klasco, M.D., FACEP. Last Annual Review Date: May 2, 2011 Copyright: © Copyright 2011 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Heart, Blood and Circulation