Hypercalcemia: Understanding High Calcium Levels and Their Impact on Health

What is hypercalcemia?

Hypercalcemia occurs when calcium levels in the blood rise above the normal range of 8.5 to 10.5 mg/dL. Calcium is a vital mineral for strong bones, nerve function, muscle contraction, and blood clotting. However, excessive calcium can disrupt these functions and lead to serious health problems.

Mild hypercalcemia may not show noticeable symptoms, but as levels increase, individuals might experience fatigue, nausea, increased thirst, or frequent urination. Severe hypercalcemia causes kidney stones, heart rhythm abnormalities, or even life-threatening complications like kidney failure. This condition often results from overactive parathyroid glands, excessive vitamin D intake, certain medications, or underlying health issues like cancer. Diagnosis involves blood tests and identifying the underlying cause.

Early hypercalcemia treatment is crucial to managing it effectively and preventing complications, emphasising the importance of regular health monitoring and consultations with a healthcare professional.

What is the difference between hypocalcemia and hypercalcemia?

It is essential to distinguish between two conditions related to calcium imbalances in the body:

• Hypocalcemia: This condition occurs when blood calcium levels are abnormally low, typically below 8.5 mg/dL. Symptoms of hypocalcemia may include muscle cramps, spasms, and neurological issues such as seizures and confusion.
• Hypercalcemia: In contrast, hypercalcemia causes abnormally high blood calcium levels, usually above 10.5 mg/dL. Hypercalcemia symptoms can range from mild to severe and may include constipation, nausea, abdominal pain, and in severe cases, confusion and coma.

Who does hypercalcemia affect?

Hypercalcemia can affect individuals of all ages, but it is most commonly seen in women over 50 years old, particularly postmenopausal women. This demographic is more susceptible to developing primary hyperparathyroidism, one of the leading causes of hypercalcemia. Other risk factors for hypercalcemia include certain cancers, prolonged immobilisation, and excessive intake of calcium and vitamin D supplements.

How common is hypercalcemia?

Hypercalcemia is not a rare condition, especially among older adults. It is often detected during routine blood tests, and many cases are asymptomatic. The incidence of hypercalcemia increases with age, and it is more prevalent in women after menopause.

Is hypercalcemia life-threatening?

In severe cases, hypercalcemia can be life-threatening if left untreated or if calcium levels become extremely elevated. When hypercalcemia levels exceed 18 mg/dL, it is considered a medical emergency. Severe hypercalcemia can lead to serious complications such as renal failure, cardiac arrhythmias, and even death.

What are the symptoms of hypercalcemia?

Hypercalcemia symptoms can vary depending on the severity and duration of the condition. Some common symptoms include:

• Digestive issues: Nausea, vomiting, abdominal pain, constipation, and decreased appetite
• Renal symptoms: Excessive thirst (polydipsia), frequent urination (polyuria), and pain due to kidney stones
• Musculoskeletal symptoms: Bone pain, osteoporosis, and fractures
• Neurological symptoms: Depression, memory loss, irritability, confusion, and in severe cases, coma
• Cardiac symptoms: Abnormal heart rhythms due to the effect of high calcium levels on the heart's electrical system

What causes hypercalcemia?

Several underlying conditions and factors can contribute to the development of hypercalcemia. Let's explore some of the primary hypercalcemia causes:

Primary hyperparathyroidism and hypercalcemia

Primary hyperparathyroidism is the most common cause of hypercalcemia. It occurs when one or more of the parathyroid glands become overactive and secrete excessive amounts of parathyroid hormone (PTH). PTH regulates calcium levels in the blood by increasing calcium absorption from the intestines, reducing calcium excretion by the kidneys, and stimulating the release of calcium from bones. When PTH levels are persistently elevated, it leads to hypercalcemia.

Cancers that can cause hypercalcemia

Certain cancers can lead to hypercalcemia through various mechanisms:

• Humoral Hypercalcemia of Malignancy (HHM): Some cancers, such as lung, kidney, and ovarian cancers, can secrete proteins that mimic the action of PTH, leading to increased blood calcium levels.
• Bone Metastasis: Cancers like breast, prostate, and lung cancers can spread to the bones, causing the destruction of bone tissue and releasing calcium into the bloodstream.
• Multiple Myeloma: This cancer of the plasma cells in the bone marrow can lead to bone destruction and subsequent hypercalcemia.

Medications that can cause hypercalcemia

Certain medications can contribute to the development of hypercalcemia:

• Thiazide diuretics: These medications, used to treat high blood pressure, can cause severe fluid loss, leading to a concentration of calcium in the blood.
• Lithium: This medication, used to treat bipolar disorder, can alter the set point for PTH suppression, resulting in higher calcium levels.
• Excessive intake of vitamin D and calcium supplements: Taking high doses of these supplements can increase calcium absorption from the digestive tract.
• Teriparatide and Abaloparatide: These medications, used to treat osteoporosis, can transiently increase calcium levels.

Other causes of hypercalcemia

Several other factors can contribute to the development of hypercalcemia:

• Dehydration: Low fluid levels in the body can concentrate calcium in the blood.
• Granulomatous diseases: Conditions like sarcoidosis and tuberculosis can increase vitamin D levels, leading to enhanced calcium absorption.
• Prolonged immobilisation: Extended periods of bed rest or immobilisation can lead to bone resorption and increased blood calcium levels.
• Severe hyperthyroidism: An overactive thyroid gland can stimulate bone resorption, releasing calcium into the bloodstream.
• Milk-alkali syndrome: Excessive intake of milk and calcium-containing antacids can lead to hypercalcemia.

How is hypercalcemia diagnosed?

Diagnosing hypercalcemia involves a combination of clinical evaluation and laboratory tests. The first step is usually a blood test to measure total calcium levels. If the calcium level is elevated, additional tests may be performed to determine the underlying cause.

These tests may include:

• Ionized calcium test: This test measures the active form of calcium in the blood, providing a more accurate assessment of calcium status.
• PTH test: Measuring PTH levels can help determine if primary hyperparathyroidism is the cause of hypercalcemia.
• Vitamin D test: Evaluating vitamin D levels can help identify vitamin D toxicity or granulomatous diseases as potential causes.
• Imaging tests: X-rays, bone scans, or CT scans may be used to detect bone abnormalities or tumours that could be contributing to hypercalcemia.
• Urine calcium test: This test measures calcium excretion in the urine, which can help differentiate between various causes of hypercalcemia.

What tests will be done to diagnose this condition?

Diagnosing hypercalcemia involves a combination of clinical evaluation, laboratory tests, and imaging studies. Here are the key tests used:

• Serum Calcium: An initial diagnosis is often made through routine blood tests showing elevated total or ionized calcium levels. Normal serum calcium ranges from 8-10 mg/dL, and hypercalcemia levels are categorised as:
  • Mild (10.5-11.9 mg/dL)
  • Moderate (12.0-13.9 mg/dL)
  • Severe or hypercalcemic crisis (14.0-16.0 mg/dL)
• Parathyroid Hormone (PTH): This critical test helps distinguish between PTH-dependent and PTH-independent hypercalcemia causes. Elevated or normal PTH suggests primary hyperparathyroidism, while suppressed PTH indicates other causes.
• Other Laboratory Tests: These include measurements of phosphorus, magnesium, alkaline phosphatase, vitamin D, glomerular filtration rate, PTH-related protein, serum and urine electrophoresis, thyroid panel, and serum metanephrines to identify the underlying cause.

How is hypercalcemia treated?

Hypercalcemia treatment depends on the severity and underlying cause. Here's an overview of the treatment approaches:

• Mild Hypercalcemia: Observation with regular monitoring may be sufficient for asymptomatic patients with mild hypercalcemia due to primary hyperparathyroidism, especially if there's no evidence of skeletal or kidney disease.
• Symptomatic or Severe Hypercalcemia:
  • Hydration with intravenous fluids to correct dehydration and enhance renal excretion of calcium
  • Bisphosphonates like zoledronic acid or pamidronate to reduce bone resorption and lower calcium levels
  • Glucocorticoids for hypercalcemia due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, certain lymphomas)
  • Denosumab and dialysis for patients with kidney failure
• Specific Treatments Based on Cause:
  • Primary Hyperparathyroidism: Parathyroidectomy may be considered based on age, serum calcium levels, and the presence of kidney or skeletal involvement.
  • Hypercalcemia of Malignancy: Treatment focuses on the underlying malignancy, with additional measures to manage hypercalcemia symptoms.

How can we prevent hypercalcemia?

Prevention strategies for hypercalcemia focus on managing underlying conditions and avoiding certain medications or supplements:

• Medication Management: Avoid or use with caution medications known to cause hypercalcemia, such as thiazide diuretics, calcium supplements, and vitamin D supplements.
• Monitoring: Regular monitoring of serum calcium levels in patients with conditions that can lead to hypercalcemia, such as primary hyperparathyroidism or malignancy.
• Dietary Considerations: Avoid excessive intake of calcium and vitamin D, especially in individuals with predisposing conditions.

What is the outlook for hypercalcemia?

The outlook for hypercalcemia varies depending on the underlying cause and severity:

• Primary Hyperparathyroidism: Asymptomatic patients often have an excellent prognosis with either medical or surgical management. Parathyroidectomy can provide long-term resolution.
• Hypercalcemia of Malignancy: This is associated with a poorer prognosis due to the underlying cancer.
• Severe Hypercalcemia: Rapidly developing severe hypercalcemia can be life-threatening and requires immediate medical intervention.

What are the complications of hypercalcemia?

Hypercalcemia can lead to several complications if left untreated:

• Kidney stones and kidney damage
• Bone loss and fractures
• Gastrointestinal issues like constipation, nausea, and vomiting
• Neurological problems such as confusion, fatigue, and depression
• Cardiovascular complications including arrhythmias and hypertension

When to see a doctor?

If you experience any hypercalcemia symptoms such as excessive thirst, frequent urination, fatigue, confusion, abdominal pain, or muscle weakness, consult your healthcare provider promptly. Early diagnosis and appropriate treatment for hypercalcemia can prevent complications and improve outcomes.

Conclusion

If you suspect you may have hypercalcemia or experience any concerning symptoms, it is crucial to consult with a healthcare professional. They can perform the necessary tests, determine the underlying cause, and develop an appropriate hypercalcemia treatment plan based on your specific needs.

At Metropolis Healthcare, we understand the importance of accurate and reliable diagnostic testing. Our team of skilled phlebotomists can conveniently collect blood samples from the comfort of your home, ensuring a hassle-free experience. With our state-of-the-art laboratories and advanced testing techniques, you can trust us to provide precise results and valuable insights into your health status.