Hypercalcemia of malignancy in the palliative care patient: a treatment strategy.

Hypercalcemia of malignancy is most commonly due to the effects of parathyroid hormone-related peptide, which acts as a humoral factor to cause generalized osteoclast-mediated bone resorption and reabsorption of calcium by the kidney tubule, and may also act as a local resorptive factor adjacent to bone metastases. Local resorptive mechanisms are less common causes of malignant hypercalcemia than previously believed. Treatment begins with intravenous fluid rehydration, followed by a furosemide diuresis and the bisphosphonate pamidronate, 60-90 mg, intravenously. Gallium nitrate is an efficacious but inconvenient alternative to pamidronate. Calcitonin combined with pamidronate is a reasonable initial therapy for severe hypercalcemia to hasten normalization of the serum calcium. Steroids should be reserved for hypercalcemia due to tumor production of 1,25 dihydroxyvitamin D, or for steroid-responsive malignancies. Oral or parenteral bisphosphonates can be used to maintain normocalcemia. In addition to improving the morbidity of acute hypercalcemia, bisphosphonate therapy has been shown to reduce bone pain and pathological fractures in patients with bone metastases, and calcitonin also has a potent analgesic effect in these patients. Treatment for hypercalcemia should therefore be considered in the majority of patients in the palliative care setting.