Frequency of kidney disease in chronic sarcoidosis.

Introduction: Sarcoidosis is an immunemediated disease of unknown cause, characterized by noncaseating epithelioid granulomas, affecting multiple organs. Clinically apparent renal involvement is rare and has been documented mostly as case reports. The incidence of renal involvement ranges from 3-23% with a wide spectrum of abnormalities.

Aim: The aim of this study was to ivestigate the renal involvement in patients with sarcoidosis.

Results: From 1995 to 2002 we diagnosed 46 patients with sarcoidosis. Fifteen patients suffered from acute sarcoidosis with arthritis, mediastinal adenopathy and erythema nodosum (Löfgren's-syndrome). Thirty-one patients had chronic sarcoidosis with organ involvement, such as granulomatous hepatitis, uveitis and pulmonary sarcoidosis. In 15 patients we found renal abnormalities, 10 patients underwent kidney biopsy. Six patients had nephrocalcinosis, 2 patients granulomatous interstitial nephritis, one patient interstitial nephritis without granuloma, and 1 patient suffered from IgA-glomerulonephritis. In 2 patients we found a combination of granulomatous interstitial nephritis either with nephrocalcinosis or with IgA-glomerulonephritis. In all patients the serum creatinine decreased after treatment with corticosteroids.

Conclusion: In our retrospective analysis we found renal abnormalities in about 48% of patients with chronic sarcoidosis, but never in patients with acute sarcoidosis (Löfgren's syndrome). We conclude that kidney involvement in chronic sarcoidosis is more frequent than previously reported.