Your bones are mostly made of calcium, but 1% of your body's calcium is in the blood. Calcium helps your body form bones and promotes normal nerve, muscle, and brain function. Your body regulates the level of calcium in many different ways. Kidneys and parathyroid hormone play a big role in this. The parathyroid gland releases parathyroid hormone, and the kidneys work to expel excess calcium out of your blood.

The reference range of calcium in blood varies among laboratories, but is generally within 8.7-10.4 mg/dL. The levels are a bit higher in children. About 50% of calcium binds itself to protein (albumin), whereas the remaining is ionized and is found in physiologic active form. Due to certain reasons, some people have more calcium in their blood than normal. This is called hypercalcemia, which may have life-threatening consequences, especially when it happens due to hypercalcemia of malignancy.

What Causes Hypercalcemia?

Hypercalcemia refers to a condition in which the levels of calcium in your body rise quickly. This usually happens when you are suffering from cancer. It may produce life-threatening consequences.

Cancer: Hypercalcemia of Malignancy

Up to 20% of patients with malignancies develop hypercalcemia at some stage, which makes malignancy the most common cause of hypercalcemia. The risks are higher with certain types of cancers, such as squamous cell head and neck cancers, squamous cell lung, multiple myeloma, breast cancer, renal cell cancer, t-cell lymphomas, and ovarian cancer.

Other Causes of Hypercalcemia

Hypercalcemia of malignancy is definitely one of the leading causes of this condition, but that may happen due to some other medical problems as well.

• Overactive Parathyroid Glands: Overactive parathyroid glands may result in hypercalcemia. This usually happens when a noncancerous tumor develops on one or more of the parathyroid glands.
• Immobility: People with cancer or those suffering from another disease that causes them to spend more time on bed may lead to the development of hypercalcemia. Bones will also release more calcium into the blood when they stop bearing weight.
• Medications: Use of certain drugs such as lithium, which is used as a treatment option for bipolar disorders, may increase the risk of developing hypercalcemia.
• Supplements: Taking calcium supplements or vitamin D supplements may raise levels of calcium in your blood.
• Hereditary Factors: Familial Hypocalciuric Hypercalcemia (FHH) is a rare genetic disorder that may raise the levels of calcium in your blood. People with this genetic disorder have faulty calcium receptors in their body.
• Dehydration: A mild form of hypercalcemia may occur due to dehydration. Levels of calcium go up when you have less fluid in your blood.
• Other Diseases: Certain diseases such as sarcoidosis and tuberculosis raise levels of vitamin D in blood, which in turn stimulates digestive tract to absorb more calcium.

Why Does Hypercalcemia of Malignancy Happen?

Hypercalcemia of malignancy may indicate the spread of cancer to bones in the body – this works through a process called metastasis. Cancer cells can spread to other parts of the body through the blood and lymph systems. Sometimes, cancer spreads to bones from the adjacent cancer, which results in injury to the bone tissue.

Bone may appear static, but it is actually very dynamic and remodels itself constantly. Humans recycle up to 7% of their bone mass every week. Bone remodeling also regulates blood calcium levels. Only 1% of the calcium in the body is reserved for several processes such as nerve function, contraction of muscles, cell division, and blood clotting. The rest of it is in the bones. Bones release calcium when there is a shortage of calcium in the blood. Hypercalcemia of malignancy disturbs this balance and makes bones to release more calcium into the bloodstream.

What Are the Signs and Symptoms of Hypercalcemia?

The condition develops very slowly and there are no real symptoms in the beginning. Some patients may experience more symptoms early, while others may not until it becomes worse. Some of the most common symptoms are nausea, vomiting, loss of appetite, headaches, fatigue, increased thirst, frequent urination, constipation, and depression. Sever hypercalcemia may produce symptoms such as irregular heartbeat, coma, loss of consciousness, kidney stones, and heart attack.

How Is Hypercalcemia Diagnosed?

A blood test confirms if a person has hypercalcemia. The test checks blood calcium levels. The levels are considered normal if the result is between 8.5 and 10.5mg per deciliter. Tests may be repeated a couple of times to confirm elevated calcium levels.

How Is Hypercalcemia of Malignancy Treated?

There are a number of ways to make this condition more manageable.

• Hydration: Increasing oral fluid intake is one of many ways to treat hypercalcemia. Some cases require intravenous administration of fluids. Fluids dilute the concentration of calcium and helps your body eliminate excess calcium through urine.
• Diuretics: The use of diuretics may help as well. Furosemide is one of the most commonly using diuretics that encourages the kidneys to produce more urine. It also promotes loss of sodium, calcium, and potassium.
• Bisphosphonates: The use of bisphosphonate drugs helps prevent loss of bone that may happen in case of metastatic lesions. This decreases pain and reduces the risk of fractures. These drugs inhibit bone breakdown to lower the levels of calcium in the blood.

Things You Can Do to Help Prevent and Manage Hypercalcemia

Besides getting treated for hypercalcemia of malignancy, you may also try the following tips to improve your condition.

• Drink plenty of water and fluids
• Take steps to keep nausea and vomiting under control
• Live an active life to prevent bones from breaking down
• Do not take any medications before consulting with your doctor