From the Guidelines
Hypercalcemia is primarily caused by malignancy, primary hyperparathyroidism, and excess bone resorption.
Causes of Hypercalcemia
- Malignancy: Hypercalcemia of malignancy is most commonly seen in patients with squamous cell lung cancer and is caused by parathyroid hormone-related protein (PTHrP) production, increased active metabolite of vitamin D (calcitriol), and localized osteolytic hypercalcemia 1.
- Primary Hyperparathyroidism: Characterized by elevated intact parathyroid hormone (iPTH) levels and calcitriol levels 1.
- Excess Bone Resorption: Can lead to excessive release of calcium into the blood, contributing to hypercalcemia, often seen in multiple myeloma 1.
Key Factors
- PTHrP-mediated hypercalcemia is characterized by a suppressed intact parathyroid hormone (iPTH) level and a low or normal calcitriol level 1.
- Symptoms of hypercalcemia include polyuria, polydipsia, nausea, confusion, vomiting, abdominal pain, and myalgia 1.
From the Research
Causes of Hypercalcemia
The causes of hypercalcemia can be categorized into several groups, including:
- Primary hyperparathyroidism (PHPT) and malignancy, which account for approximately 90% of cases 2
- Granulomatous disease, such as sarcoidosis 2
- Endocrinopathies, such as thyroid disease 2
- Immobilization 2
- Genetic disorders 2
- Medications, including:
- Supplements, including:
- Other causes, such as:
Less Common Causes
Less common causes of hypercalcemia include:
- Breast cancer, which can cause hypercalcemia through the secretion of parathyroid hormone-related protein (PTHrP) 6
- Other malignancies, such as multiple myeloma and lymphoma 3
Iatrogenic Causes
Iatrogenic causes of hypercalcemia, such as thiazide-induced hypercalcemia, can be severe and require prompt treatment 4