Elevated 1,25-dihydroxyvitamin D levels: occurrence with sarcoidosis with end-stage renal disease

It is generally agreed that the kidneys are the only site of 1-hydroxylation of vitamin D and that the abnormal calcium metabolism in sarcoidosis is caused by increased production of 1,25-dihydroxyvitamin D (1,25-[OH]2D). We describe a patient with sarcoidosis with hypercalcemic nephropathy and end-stage renal disease undergoing long-term maintenance hemodialysis who was initially seen with hypercalcemia and elevated serum levels of 1,25-(OH)2D. Prednisone administration resulted in decreased serum calcium and 1,25-(OH)2D levels. These results confirm the recent evidence for extrarenal production of 1,25-(OH)2D in sarcoidosis and illustrate the importance of altered vitamin D metabolism in the development of hypercalcemia in sarcoidosis.