What is Hypercalcemia?
Hypercalcemia refers to the condition characterized by an elevated level of calcium in the blood. While calcium is essential for various bodily functions, including bone health, muscle contraction, and nerve signaling, its excess can lead to serious health complications.
Why is Hypercalcemia Significant in Cancer Patients?
Hypercalcemia is a common complication in cancer patients, often indicating a poor prognosis. It occurs in up to 30% of cancer cases, especially among patients with advanced stages of the disease. The most common cancers associated with hypercalcemia include
breast cancer,
lung cancer, and multiple myeloma. This condition is significant because it can exacerbate the patient's symptoms and affect their quality of life.
Humoral Hypercalcemia of Malignancy (HHM): This is the most common cause, where tumor cells secrete parathyroid hormone-related protein (PTHrP), which mimics the action of parathyroid hormone (PTH) and increases calcium levels.
Bone Metastases: Cancers that metastasize to the bone can cause local bone resorption, releasing calcium into the bloodstream.
Vitamin D production by tumors: Some tumors can produce active vitamin D, which increases calcium absorption from the gut.
PTH secretion: Rarely, tumors can secrete actual PTH.
Mild Hypercalcemia: May be asymptomatic or cause nonspecific symptoms like fatigue, nausea, and constipation.
Moderate Hypercalcemia: Can cause more pronounced symptoms such as abdominal pain, dehydration, and confusion.
Severe Hypercalcemia: Can lead to severe complications like kidney stones, arrhythmias, coma, and even death.
How is Hypercalcemia Diagnosed?
Diagnosis involves measuring serum calcium levels. If hypercalcemia is detected, further tests are conducted to understand the underlying cause. This may include measuring PTH, PTHrP, vitamin D levels, and imaging studies to check for bone metastases.
Hydration: Intravenous (IV) fluids are administered to enhance renal calcium excretion.
Bisphosphonates: These drugs inhibit bone resorption and are commonly used to treat hypercalcemia of malignancy.
Calcitonin: This hormone can lower calcium levels quickly but is usually used for short-term management.
Glucocorticoids: Effective in certain types of hypercalcemia, especially those related to vitamin D production by tumors.
Dialysis: Used in severe cases where other treatments are ineffective or contraindicated.
Can Hypercalcemia be Prevented?
Preventive measures are limited but may include regular monitoring of calcium levels in high-risk patients and early treatment of bone metastases. Prophylactic use of bisphosphonates in patients with bone metastases can also help in reducing the risk of hypercalcemia.
