HYPERCALCEMIA
Hypercalcemia is a condition in which the calcium level in the blood is above normal.
Too much calcium in blood can weaken bones, create kidney stones, and interfere with normal heart and brain work.
MECHANISM OF HYPERCACEMIA
Hypercalcemia is usually a result of overactive parathyroid glands. These four tiny glands are situated in the neck, near the thyroid gland.
Other causes of hypercalcemia include cancer, certain other medical disorders, some medications, and taking too much of calcium and vitamin D supplements.
Besides building strong bones and teeth, calcium helps muscles contract and nerves transmit signals. Normally, if there isn't enough calcium in blood, the parathyroid glands secrete a hormone that triggers:
Bones to release calcium into the blood
The digestive tract to absorb more calcium
The kidneys excrete less calcium and activate more vitamin D, which plays a vital role in calcium absorption
This delicate balance between too little calcium in blood and hypercalcemia can be disrupted by a variety of factors.
CAUSES
Hypercalcemia is caused by:
Overactive parathyroid glands (hyperparathyroidism)
This most common cause of hypercalcemia 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 blood cancers, can increase risk of hypercalcemia. Spread of cancer (metastasis) to bones also increases risk.
Other diseases
Certain diseases, such as tuberculosis and sarcoidosis, can raise blood levels of vitamin D, which stimulates the digestive tract to absorb more calcium.
Hereditary factors
A rare genetic disorder known as familial hypocalciuric hypercalcemia causes an increase of calcium in the blood because of faulty calcium receptors in body.
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 blood causes a rise in calcium concentrations.
Medications
Certain drugs — such as lithium, 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.
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