Renal sarcoidosis with superimposed postinfectious glomerulonephritis presenting as acute renal failure

We describe two patients with sarcoidosis with lesions of granulomatous interstitial nephritis (GIN) and postinfectious glomerulonephritis (GN). Both patients presented with heavy proteinuria, hematuria, and renal failure. Renal histology in both showed GIN and glomerular changes of proliferative GN with hump-like subepithelial deposits by electron microscopy of postinfectious GN. Antecedent history of pneumonia was present in one, and ASO titer was elevated in the other. The proteinuria and azotemia improved in both with steroid therapy. Reports of "postinfectious" or diffuse proliferative GN in patients with sarcoidosis are rare. The authors are unaware of reports of concomitant sarcoid GIN and postinfectious GN. Although acute renal insufficiency or failure can occur with GIN or other more common renal lesions primary glomerular disease should be considered in patients with sarcoidosis who present with renal dysfunction. This is a US government work. There are no restrictions on its use.