Renal insufficiency in sarcoidosis. A clinical and pathologic study.

The relationship of sarcoidosis to renal insufficiency is not widely known by pathologists or clinicians. During an 8-year period beginning in 1980, we observed six patients with sarcoidosis and clinically significant renal insufficiency (serum creatinine, greater than 260 mumol/L). In one of these patients with long-standing sarcoidosis, renal insufficiency was attributed to unrelated primary renal disease until renal biopsy specimen showed interstitial noncaseating granulomas. The four patients with renal insufficiency at presentation differed from the typical patient with sarcoidosis because they were white men who lacked the usual clinical constellation of skin, eye, and pulmonary involvement. All four had noncaseating granulomas on their initial biopsy (bone marrow [3 patients], and lymph node [1 patient]), suggesting each had sarcoidosis, yet each had two or more follow-up biopsies before the diagnosis of sarcoidosis was accepted and appropriate therapy initiated. One of these four patients underwent long-term antifungal and antituberculous therapy. The major causes of renal insufficiency in these six patients were complications of hypercalcemia and interstitial granulomatous nephritis. Except in one patient with nephrocalcinosis, prednisone therapy resulted in a dramatic fall in serum creatinine level with resolution of hypercalcemia. Sarcoidosis is a rare, but treatable, cause of renal insufficiency. Early recognition by clinicians and pathologists may spare patients from undergoing unnecessary biopsies and result in more timely initiation of therapy.