Hypercalcaemia

Overview Of Hypercalcaemia

Hypercalcemia refers to an elevated level of calcium in the blood, which can lead to various symptoms affecting different systems of the body, including the bones, kidneys, gastrointestinal tract, and cardiovascular system. Calcium plays an essential role in the body, involved in processes such as muscle function, nerve signaling, blood clotting, and bone health. However, when blood calcium levels become too high, it can disrupt these functions. Hypercalcemia can be a result of several underlying conditions, ranging from relatively benign causes to more serious diseases such as cancer or hyperparathyroidism. Symptoms can range from mild and nonspecific to severe, with some individuals experiencing fatigue, weakness, kidney stones, bone pain, or even life-threatening complications. Treatment depends on the underlying cause and the severity of the hypercalcemia.

Causes of Hypercalcaemia

• There are several possible causes of hypercalcemia, including: - Primary Hyperparathyroidism: The most common cause of hypercalcemia in outpatient settings, this occurs when one or more of the parathyroid glands produce too much parathyroid hormone (PTH), which increases calcium levels by promoting calcium release from bones, increasing calcium absorption in the intestines, and reducing calcium excretion by the kidneys. - Malignancy: Certain cancers, especially lung, breast, and multiple myeloma, can cause hypercalcemia. Tumors can either produce parathyroid hormone-related protein (PTHrP), which mimics PTH activity, or metastasize to bone, causing calcium release from the bones. - Vitamin D Overdose: Excessive intake of vitamin D can lead to increased calcium absorption from the gastrointestinal tract, potentially causing hypercalcemia. - Thiazide Diuretics: These medications, commonly used for managing high blood pressure or fluid retention, can reduce calcium excretion by the kidneys, leading to increased calcium levels in the blood. - Chronic Kidney Disease: Impaired kidney function can result in calcium imbalances, as the kidneys play a key role in regulating calcium levels in the body. In some cases, kidney disease leads to excess calcium in the blood. - Granulomatous Diseases: Conditions such as sarcoidosis or tuberculosis can cause abnormal activation of vitamin D, increasing calcium absorption and leading to hypercalcemia. - Prolonged Immobilization: In situations where a person is immobilized for long periods (e.g., due to spinal cord injury), calcium may be released from bones into the bloodstream, causing elevated calcium levels.

Risk Factors of Hypercalcaemia

• Several factors increase the likelihood of developing hypercalcemia: - Age: Hypercalcemia is more common in adults, particularly in older individuals, due to conditions like hyperparathyroidism and age-related changes in calcium metabolism. - Cancer: People with certain cancers, especially lung, breast, and multiple myeloma, are at an increased risk of hypercalcemia due to cancer-related processes like bone metastases or the secretion of PTHrP. - Hyperparathyroidism: Having primary hyperparathyroidism, which is more common in women and older adults, significantly increases the risk of hypercalcemia due to excess parathyroid hormone production. - Kidney Disease: Chronic kidney disease can disrupt calcium regulation and increase the risk of hypercalcemia, especially in advanced stages of the disease. - Vitamin D Supplementation: Overuse of vitamin D supplements, especially in individuals with underlying health conditions that predispose them to hypercalcemia, can contribute to high calcium levels. - Medications: Certain medications, such as thiazide diuretics or lithium (used in bipolar disorder), increase the risk of hypercalcemia due to their effects on calcium metabolism.

Prevention of Hypercalcaemia

• Prevention of hypercalcemia largely involves managing risk factors and avoiding its causes: - Monitoring Calcium Intake: Limiting the intake of vitamin D supplements and avoiding excessive calcium supplementation can help prevent hypercalcemia, especially in individuals at risk. - Treating Underlying Conditions: Managing conditions like hyperparathyroidism, cancer, and kidney disease effectively can reduce the risk of developing hypercalcemia. - Regular Screening: For individuals at higher risk, such as those with a family history of hyperparathyroidism or malignancy, regular blood tests to monitor calcium levels may be recommended. - Staying Hydrated: Proper hydration, especially in individuals prone to kidney stones or other calcium-related issues, can help prevent hypercalcemia by promoting calcium excretion.

Prognosis of Hypercalcaemia

• The prognosis for individuals with hypercalcemia depends on the underlying cause and how effectively it is treated. Mild cases may resolve with simple interventions like hydration or adjustment of medications, while more severe cases, especially those related to cancer, may require ongoing management. If untreated, severe hypercalcemia can lead to life-threatening complications, including kidney failure, cardiac arrhythmias, and coma.

Complications of Hypercalcaemia

• Uncontrolled or severe hypercalcemia can lead to significant complications: - Kidney Stones: High calcium levels in the urine can lead to the formation of kidney stones, which can cause pain, hematuria, and obstruction of the urinary tract. - Kidney Damage: Prolonged hypercalcemia can cause damage to the kidneys, potentially resulting in kidney failure if not addressed. - Cardiac Arrhythmias: Excess calcium can disrupt the electrical activity of the heart, increasing the risk of arrhythmias, which can be life-threatening. - Osteoporosis: Chronic high calcium levels can cause bone resorption, leading to weakened bones and an increased risk of fractures.

Related Diseases of Hypercalcaemia

• Hypercalcemia can be related to several other medical conditions, including: - Primary Hyperparathyroidism: A common cause of elevated calcium levels due to overproduction of parathyroid hormone. - Malignancies: Cancers like lung, breast, and multiple myeloma can cause hypercalcemia through metastasis or secretion of PTH-related proteins. - Sarcoidosis: This granulomatous disease can cause vitamin D activation, leading to elevated calcium levels. - Chronic Kidney Disease: Impaired renal function can contribute to calcium imbalances, sometimes leading to hypercalcemia. - Thyrotoxicosis: Overactive thyroid conditions can sometimes lead to calcium elevation, particularly in the context of bone resorption.

Treatment of Hypercalcaemia

The treatment of hypercalcemia focuses on addressing the underlying cause and reducing calcium levels to prevent complications. Treatment options include: - **Hydration**: Intravenous fluids, especially saline, are often given to increase kidney function and promote calcium excretion. Hydration helps dilute calcium levels in the blood and enhances renal calcium clearance. - **Medications**: - **Bisphosphonates**: These medications, such as zoledronic acid, inhibit bone resorption and are often used when hypercalcemia is caused by malignancy or hyperparathyroidism. - **Calcitonin**: This hormone helps lower calcium levels by inhibiting bone resorption and increasing renal calcium excretion. It is often used in acute cases. - **Corticosteroids**: In cases where hypercalcemia is due to granulomatous diseases (e.g., sarcoidosis), corticosteroids may be used to reduce inflammation and calcium absorption. - **Dialysis**: In severe cases of hypercalcemia, especially in patients with kidney failure, hemodialysis may be required to rapidly remove excess calcium from the blood. - **Surgical Intervention**: If hypercalcemia is caused by primary hyperparathyroidism, surgery to remove the overactive parathyroid gland(s) may be necessary to normalize calcium levels. - **Treating Underlying Conditions**: If a specific underlying condition, such as cancer or excessive vitamin D intake, is identified, treatment for that condition will be necessary to manage hypercalcemia.