Caution in the Use of Phosphates in the Treatment of Severe Hypercalcemia

Abstract

Recently, interest in the use of inorganic phosphates in the treatment of severe symptomatic hypercalcemia has been renewed. The history of a patient with nausea, vomiting, somnolence, dehydration and bone pain is presented. Serum calcium concentration was 17.8 mg/100 ml and a primary diagnosis of plasma cell myeloma was established. Intravenous and oral inorganic phosphate treatment resulted in initial clinical improvement and a decline in serum calcium value to 8.5 mg/100 ml. However, calciuria abruptly ceased and renal failure ensued. Post-mortem examination demonstrated extensive extraskeletal calcification, especially in kidney and lungs. The physiologic basis for rapid extraskeletal calcium deposition is reviewed. The potential risk of extraskeletal calcification when inorganic phosphates are used to treat hypercalcemia is emphasized.