Renal Failure and Hypercalcemia as Initial Manifestations of Extrapulmonary Sarcoidosis

Sarcoidosis is a granulomatous, multisystem disease. Rarely, sarcoidosis may present with both renal failure and hypercalcemia. A 27-year-old black man presented with severe abdominal pain and renal failure. A kidney biopsy demonstrated features of both interstitial nephritis and membranous glomerulopathy thought to be secondary to nonsteroidal anti-inflammatory drugs. His renal function and symptoms improved with short-term prednisone therapy. Discontinuation of steroids led to a recurrence of renal failure and severe hypercalcemia. On the basis of an elevated angiotensin-converting enzyme level of 160 U/L and anemia, a bone marrow biopsy was performed. Acid-fast bacillus-negative, noncaseating granulomas suggested the diagnosis of sarcoidosis. The patient recovered after restarting prednisone. Sarcoidosis may cause both interstitial and membranous nephritis from direct infiltration. Hypercalcemia results from increased calcium absorption secondary to 1,25-dihydroxyvitamin D production by sarcoid granulomas. Sarcoidosis must be considered in the differential diagnosis of renal failure in black patients. Serum calcium and angiotensin-converting enzyme levels may aid the diagnosis.