Evaluation and therapy of hypercalcemia.

Hypercalcemia is a common but challenging disorder. It results from PTH-dependent or independent increased bone resorption, increased vitamin D-dependent absorption, or as a result of various drugs and substances. Outpatient hypercalcemia is most commonly caused by primary hyperparathyroidism while malignancy accounts for most inpatient disease. Treatment includes adequate hydration, intravenous bisphosphonates, and occasionally calcitonin as a temporizing measure. Treating the underlying cause, such as employing chemotherapy for malignancy or parathyroidectomy for hyperparathyroidism, is also essential.