Published: 18 Jun 2025

ICD9: 275.42      ICD10: E83.52      ICD11: 5B91.0

Hypercalcemia is a condition in which the calcium level in your blood is higher than normal.
Calcium is important for many functions, including:

Bone health: Calcium is a major building block of bones.
Muscle contraction: Calcium helps muscles contract properly.
Nerve function: Calcium is involved in nerve transmission.
Blood clotting: Calcium is essential for blood clotting.

Normal calcium levels in adults generally range from 8.5 to 10.2 mg/dL (milligrams per deciliter). Hypercalcemia is usually defined as a level above 10.2 mg/dL. However, the specific reference range can vary slightly between different laboratories.

Causes of Hypercalcemia:

Hypercalcemia has many potential causes, but the two most common are:

Hyperparathyroidism: This is an overactivity of one or more of the parathyroid glands, which are four small glands in the neck that regulate calcium levels. The overactive gland produces too much parathyroid hormone (PTH), which leads to increased calcium release from bones and increased calcium absorption from the intestines and kidneys. It is often caused by a benign tumor on one of the glands.
Cancer: Certain cancers, such as lung cancer, breast cancer, and multiple myeloma, can cause hypercalcemia. They can do this by:
Producing a substance similar to PTH that stimulates bone breakdown.
Spreading to the bones and directly causing calcium release.

Other less common causes of hypercalcemia include:

Certain medications: Thiazide diuretics (water pills), lithium, and some antacids can increase calcium levels.
Vitamin D toxicity: Excessive intake of vitamin D can lead to increased calcium absorption.
Kidney disease: In some cases, kidney problems can affect calcium regulation.
Sarcoidosis and tuberculosis: These inflammatory diseases can affect calcium metabolism.
Immobilization: Prolonged bed rest or immobility can lead to bone loss and increased calcium in the blood.
Dehydration: Severe dehydration can concentrate the calcium in the blood, leading to hypercalcemia.
Familial hypocalciuric hypercalcemia (FHH): This is a rare inherited condition that causes mild, lifelong hypercalcemia. It is usually asymptomatic.

Symptoms of Hypercalcemia:

Many people with mild hypercalcemia have no symptoms. When symptoms do occur, they can vary depending on the severity of the condition and how quickly it develops. Possible symptoms include:

Mild Hypercalcemia:
Fatigue
Weakness
Increased thirst
Frequent urination
Constipation
Bone pain
Abdominal pain
Nausea and vomiting
Loss of appetite

Severe Hypercalcemia:
Confusion, lethargy
Severe constipation
Kidney stones
Pancreatitis
Abnormal heart rhythm (arrhythmia)
Muscle weakness
Depression
Coma

Diagnosis:

Hypercalcemia is usually diagnosed through a routine blood test. If high calcium levels are detected, further tests may be needed to determine the underlying cause, such as:

Parathyroid hormone (PTH) level: To check for hyperparathyroidism.
Vitamin D level: To rule out vitamin D toxicity.
Kidney function tests: To assess kidney function.
Blood and urine tests: To look for signs of cancer.
Imaging tests: Such as X-rays, CT scans, or bone scans, to look for bone abnormalities or tumors.

Treatment:

The treatment for hypercalcemia depends on the severity of the condition and the underlying cause. Treatment options may include:

Mild Hypercalcemia:
Hydration: Drinking plenty of fluids to help flush calcium out of the system.
Monitoring: Regular blood tests to monitor calcium levels.
Dietary changes: Avoiding excessive calcium and vitamin D intake.

Moderate to Severe Hypercalcemia:
Intravenous fluids: To rehydrate the body and dilute the calcium in the blood.
Calcitonin: A hormone that helps lower calcium levels by inhibiting bone breakdown.
Bisphosphonates: Medications that help prevent bone breakdown.
Diuretics (loop diuretics): Help the kidneys eliminate excess calcium.
Dialysis: In severe cases, dialysis may be necessary to remove calcium from the blood.

Treatment of the underlying cause: If hypercalcemia is caused by hyperparathyroidism, surgery to remove the overactive parathyroid gland may be necessary. If it's caused by cancer, treatment will focus on managing the cancer.

Complications of Hypercalcemia:

If left untreated, hypercalcemia can lead to various complications, including:

Kidney stones: High calcium levels can increase the risk of kidney stone formation.
Kidney failure: Chronic hypercalcemia can damage the kidneys and lead to kidney failure.
Osteoporosis: Long-term hypercalcemia can weaken bones and increase the risk of fractures.
Arrhythmias: Hypercalcemia can disrupt the heart's electrical activity and lead to abnormal heart rhythms.
Coma: In severe cases, hypercalcemia can lead to coma.

In summary, hypercalcemia is a condition where the calcium level in the blood is higher than normal. It has various causes, with hyperparathyroidism and cancer being the most common. Symptoms can range from mild to severe, and treatment depends on the severity and underlying cause. Early diagnosis and treatment are crucial to prevent potential complications.

It is important to consult a healthcare professional for diagnosis and treatment of hypercalcemia. This information should not be considered medical advice.