Hypercalcemia is a condition in which your blood calcium level is abnormally high. Too much calcium in your blood can weaken your bones, cause kidney stones, and disrupt the functioning of your heart and brain. Overactive parathyroid glands are the most common cause of hypercalcemia. These four small glands are located near the thyroid gland in the neck. Cancer, certain other medical diseases, some medications, and taking too much calcium and vitamin D supplements are all possible causes of hypercalcemia. Hypercalcemia has a wide range of signs and symptoms, from none to severe. Treatment is determined by the underlying cause.
Hypercalcemia is caused by the following:
Hyperparathyroidism (Overactive parathyroid glands): A small, noncancerous (benign) tumor or enlargement of one or more of the four parathyroid glands is the most common cause of hypercalcemia.
Cancers: Hypercalcemia is linked to cancers such as lung and breast cancer and several other blood cancers. The spread of cancer to your bones (metastasis) may also increase your risk.
Familial hypocalciuric hypercalcemia: It is a rare genetic disorder that produces an increase in calcium in your blood due to defective calcium receptors in your body.
Immobility: Hypercalcemia can develop in people who have a condition that leads them to spend a lot of time sitting or lying down. Bones that do not bear weight release calcium into the blood over time.
Other diseases: Vitamin D levels in the blood can be increased by diseases like tuberculosis and sarcoidosis, which stimulates your digestive tract to absorb more calcium.
Severe Dehydration: Dehydration is a common cause of mild or transient hypercalcemia. Calcium concentrations rise when you have less fluid in your blood.
Supplements: Taking too much calcium or vitamin D over time can cause your blood calcium levels to rise above normal.
Medications: Some drugs, such as lithium, which is used to treat bipolar disorder, may cause an increase in parathyroid hormone release.
If hypercalcemia is mild, you may not notice any signs or symptoms. Elevated calcium levels in your blood may cause the following symptoms:
Blood Tests: Hypercalcemia has few, if any, symptoms you may not realize you have until routine blood tests detect a high level of calcium in your blood. Blood testing can also show whether you have hyperparathyroidism if your parathyroid hormone level is high. Granulomatous disease, iatrogenic causes (e.g., kidney dialysis), adrenal insufficiency, thyrotoxicosis, and vitamin D intoxication all cause low PTH levels.
Your doctor may order imaging studies of your bones or lungs to see if a disease like cancer or sarcoidosis causes your hypercalcemia. Bone abnormalities such as demineralization, bone cysts, pathological fractures, and bony metastases may be visible on plain X-rays. To detect abnormalities of the urogenital tract, such as calcification or stones, an ultrasound scan, computerized tomography (CT) scan, or intravenous pyelogram (IVP) may be required. If hypertrophy or adenoma of the parathyroid glands is suspected, an ultrasound or technetium scan of the glands may be recommended.
If your hypercalcemia is mild, you and your doctor may choose to watch and wait, monitoring your bones and kidneys over time to ensure they stay healthy. If your hypercalcemia is severe, your doctor may prescribe medications or treatment for the underlying disease. Surgery to remove the tissue causing the condition will often cure problems linked with overactive parathyroid glands. Only one of a person's four parathyroid glands is usually damaged. An injection of a small dose of radioactive material is used in a special scanning test to target the gland or glands that aren't working correctly.
Calcitonin (Miacalcin) is a fish hormone that regulates calcium levels in the blood. Mild nausea is a possible adverse effect.
Calcimimetics are a class of drugs that can help to regulate overactive parathyroid glands. Cinacalcet (Sensipar) is a drug that has been approved to treat hypercalcemia.
Bisphosphonates: Intravenous osteoporosis medications that reduce calcium levels quickly are often used to treat hypercalcemia caused by cancer. Breakdown of the jaw (osteonecrosis) and some types of thigh fractures are two risks connected with this treatment.
Denosumab (Prolia, Xgeva) is a medication used to treat cancer-related hypercalcemia in people who do not respond well to bisphosphonates.
Prednisone: If high vitamin D level causes hypercalcemia, taking steroid medications like prednisone for a short period may help.
IV fluids: You may need to be admitted to the hospital and treated with IV fluids and diuretics to quickly lower the calcium level and prevent heart rhythm problems or nervous system damage.
Complications of hypercalcemia include:
Kidney Stones: Crystals may form in your kidneys if your urine contains too much calcium. Kidney stones can occur when the crystals combine over time. It can be excruciatingly painful to pass a stone.
Osteoporosis: If your bones continue to release calcium into your blood, you could develop osteoporosis, a bone-thinning disease that can cause bone fractures, spinal column curvature, and height loss.
Kidney failure: Severe hypercalcemia can damage your kidneys, making it difficult for them to clean the blood and eliminate fluid.
Nervous system issues: Confusion, dementia, and coma, all of which can be fatal, can result from severe hypercalcemia.
Cardiac arrhythmias: The electrical impulses that regulate your heartbeat can be affected by hypercalcemia, causing your heart to beat irregularly.
Even though not all hypercalcemia can be prevented, limiting the excess intake of calcium supplements and calcium-based antacid tablets are recommended. Consult your doctor if you have a family history of high calcium, kidney stones, or parathyroid conditions. Do not take dietary supplements, vitamins, or minerals without first consulting your doctor.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 21, 2023.
Hypercalcemia: A Review | Acid Base, Electrolytes, Fluids | JAMA | JAMA Network
Hypercalcemia - StatPearls - NCBI Bookshelf (nih.gov)