The infrequency of hypercalcemia in sarcoidosis

Abstract

For many years hypercalcemia has been considered to be a rather common complication of sarcoidosis. More recently, the serum ionized fraction has been reported to be commonly elevated. These findings, combined with earlier reports of the frequent occurrence of hypercalciuria, have led to the conclusion that disorders of calcium metabolism may be a basic feature of sarcoidosis. In the present analysis measurement of total and ultrafiltrable serum calcium levels in a prospective study of 137 patients with sarcoidosis revealed no significant differences in mean values between patients and controls. Six patients had hypercalcemia at the time of initial sampling, but five were normal on subsequent examinations. Retrospective analysis of 243 other patients with sarcoidosis who had serum calcium measurements in the routine hospital laboratory between 1960 and 1968 revealed significant hypercalcemia in seven instances. In neither the prospective nor retrospective studies were serum calcium levels increased during the summer months. Thus, persistent hypercalcemia was observed in eight of 364 patients (2.2 per cent) and only in association with severe and widespread sarcoidosis. Total and ultrafiltrable magnesium and serum phosphate levels were normal. The association of hypercalcemia with severe and disseminated sarcoidosis, the current widespread use of corticosteroids in patients with progressive illness, and the suppressive effects of these agents on sarcoid granulomatosis, best explain the infrequency with which hypercalcemia is encountered in recent studies of this disease.