Malignancy-Related Hypercalcemia

Hypercalcemia is a common metabolic abnormality seen in both inpatient and outpatient settings. Depending on the serum calcium levels, hypercalcemia is categorized either as mild when levels are between 10 to 12 mg/dL, moderate when levels are between 12 to 14 mg/dL, or severe when levels are more than 14 mg/dL. Approximately, 40% to 45% of the serum calcium is attached to albumin, and serum calcium levels may fluctuate based on the serum albumin levels. Therefore, ionized or free calcium levels should be measured when hypercalcemia is suspected. The corrected calcium can be calculated by using the following formula: serum calcium + 0.8 x (4- patient’s albumin level); 4 is normal albumin level in g/dL. More than 90% of the cases of hypercalcemia are due to primary hyperparathyroidism and malignancy-induced hypercalcemia. Malignancy remains the most common cause of hypercalcemia in hospitalized patients.