What is hypercalcemia?
Calcium is a mineral that is important in the regulation and processes of many body functions including bone formation, hormone release, muscle contraction, and nerve and brain function. Hypercalcemia is the term that refers to elevated levels of calcium in the bloodstream.
Regulation of Calcium
Calcium levels are tightly regulated in the body. Calcium regulation is primarily controlled by parathyroid hormone (PTH), vitamin D, and calcitonin.
- Parathyroid hormone is a hormone produced by the parathyroid glands, which are four small glands that surround the thyroid and are found in the anterior part of the lower neck.
- Vitamin D is obtained through a process that begins with sun exposure to the skin, the process then continues in the liver and kidneys. Vitamin D can also be found in foods such as eggs and dairy products.
- Calcitonin is produced in specialized cells in the thyroid gland.
Together, these three hormones act on the bones, the kidneys, and the GI tract to regulate calcium levels in the bloodstream.
What are the symptoms for hypercalcemia?
You might not have signs or symptoms if your hypercalcemia is mild. More-severe cases produce signs and symptoms related to the parts of your body affected by the high calcium levels in your blood. Examples include:
- Kidneys. Excess calcium in your blood means your kidneys have to work harder to filter it. This can cause excessive thirst and frequent urination.
- Digestive system. Hypercalcemia can cause stomach upset, Nausea, Vomiting and constipation.
- Bones and muscles. In most cases, the excess calcium in your blood was leached from your Bones, which weakens them. This can cause bone pain, muscle Weakness and depression.
- Brain. Hypercalcemia can interfere with the way your brain works, resulting in Confusion, Lethargy and Fatigue. It can also cause depression.
- Heart. Rarely, severe hypercalcemia can interfere with your heart function, causing Palpitations and Fainting, indications of cardiac arrhythmia, and other heart problems.
When to see a doctor
Contact your doctor if you develop signs and symptoms that might indicate hypercalcemia, such as being extremely thirsty, urinating frequently and having abdominal pain.
What are the causes for hypercalcemia?
Besides building strong bones and teeth, calcium helps muscles contract and nerves transmit signals. Normally, if there isn't enough calcium in your blood, your parathyroid glands secrete a hormone that triggers:
- Your bones to release calcium into your blood
- Your digestive tract to absorb more calcium
- Your kidneys to excrete less calcium and activate more vitamin D, which plays a vital role in calcium absorption
This delicate balance between too little calcium in your blood and hypercalcemia can be disrupted by a variety of factors. Hypercalcemia is caused by:
- Overactive parathyroid glands. The most common cause of hypercalcemia, overactive parathyroid glands (hyperparathyroidism) can stem from a small, noncancerous (benign) tumor or enlargement of one or more of the four parathyroid glands.
- Cancer. Lung cancer and breast cancer, as well as some cancers of the blood, can increase your risk of hypercalcemia. Spread of cancer (metastasis) to your bones also increases your risk.
- Other diseases. Certain diseases, such as tuberculosis and sarcoidosis, can raise blood levels of vitamin D, which stimulates your digestive tract to absorb more calcium.
- Hereditary factors. A rare genetic disorder known as familial hypocalciuric hypercalcemia causes an increase of calcium in your blood because of faulty calcium receptors in your body. This condition doesn't cause symptoms or complications of hypercalcemia.
- Immobility. People who have a condition that causes them to spend a lot of time sitting or lying down can develop hypercalcemia. Over time, bones that don't bear weight release calcium into the blood.
- Severe dehydration. A common cause of mild or transient hypercalcemia is dehydration. Having less fluid in your blood causes a rise in calcium concentrations.
- Medications. Certain drugs — such as lithium, which is used to treat bipolar disorder — might increase the release of parathyroid hormone.
- Supplements. Taking excessive amounts of calcium or vitamin D supplements over time can raise calcium levels in your blood above normal.
What are the treatments for hypercalcemia?
How is hypercalcemia treated?
The treatment of elevated levels of calcium in the blood involves the evaluation of the following:
1. Is the level of calcium elevated enough to be dangerous, or is it causing symptoms?
2. What is the underlying cause of the hypercalcemia, and does it need treatment?
If the hypercalcemia is causing severe symptoms, or if the values are critically high, lowering the blood levels may require hospitalization and the use of hydration, steroids, or even dialysis. There are intravenous medications that can be used to lower calcium as well.
If the hypercalcemia is modest, treatment with medications can be administered on an outpatient basis.
If the underlying cause is hyperparathyroidism (particularly from an adenoma), there are certain criteria that are reviewed to discuss if surgery should be considered. These criteria include the absolute calcium level, a history of kidney stones or other calcium-related complications, and the amount of calcium seen in a 24-hour urine collection. Based on these findings, surgical removal of the adenoma may be considered.
What is the prognosis for hypercalcemia?
The results of treatment for hypercalcemia depend on the underlying cause of the condition. If hypercalcemia is seen in the presence of cancer, the average 30-day survival rate is about 50%. The prognosis is excellent for many of the other causes of hypercalcemia provided the underlying cause is addressed and treated.
What are the risk factors for hypercalcemia?
Women older than 50 are at highest risk of overactive parathyroid glands.