Non-Parathyroid Hypercalcemia

This chapter discusses the clinical signs and symptoms, approach to diagnosis, nonparathyroid causes and management of hypercalcemia. It presents several broad guidelines for the differential diagnosis of the causes of hypercalcemia. Malignancy-associated hypercalcemia (MAHC) accounts for approximately 90% of hypercalcemia encountered among hospitalized patients. Humoral hypercalcemia of malignancy (HHM) is the most common form of MAHC-others being LOH, 1,25(OH)₂D-induced hypercalcemia, and authentic ectopic hyperparathyroidism. Almost every single disease associated with granuloma formation has been reported to cause hypercalcemia, the most common being sarcoidosis, but tuberculosis (both from M. bovis and M. avium), berylliosis, histoplasmosis, coccidoimycosis, Pneumocystis, inflammatory bowel disease, histocytosis X, foreign body granulomas, and granulomatous leprosy have all been associated with the syndrome. The causes of hypercalcemia can be divided into two broad categories: those associated with elevated parathyroid hormone (PTH) values and those in which PTH is low normal or frankly suppressed.