Hypercalcemia is total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium concentration > 5.2 mg/dL (> 1.30 mmol/L). The most common causes of hypercalcemia are cancer and which of the following?
Paget disease of bone
Hyperparathyroidism
Vitamin D toxicity
Lithium toxicity