Renal manifestations in sarcoidosis

Clinically distinct renal disease is said to be rare in sarcoidosis, but autopsy reveals an incidence of renal involvement is 23 or 26% in Japanese studies. There are three categories of renal disease in sarcoidosis: 1) renal changes by abnormal calcium metabolism, 2) interstitial nephritis or granulomatous nephritis and 3) glomerulonephritis. Some investigators add renal angiitis to the three categories. In some patients without clinical renal disorders, renal involvement is discovered by chance at the time of autopsy or renal biopsy. Renal disease may develop during the course of sarcoidosis, preceding the diagnosis of sarcoidosis, or may be found simultaneously with extrarenal involvements at the time of diagnosis. Renal involvement should always be considered for exact diagnosis and appropriate treatment.