Granulomatous Interstitial Nephritis and Acute Renal Failure due to Renal-limited Sarcoidosis.

Renal failure secondary to granulomatous sarcoidosis without clinical features or radiological evidence of disease is rare. In this case report, we describe a 14-year old girl who developed progressive renal failure over a two-month period which was associated with weight loss and epigastric pain. Physical examination did not show any abnormality. Laboratory investigations were normal except for normocytic normochromic anemia, high serum urea, high serum creatinine (452 tmol/L) and polyclonal gammopathy. Percutaneous kidney biopsy showed severe interstitial nephritis with non-caseating granulomata. She was treated with tapered prednisone after a starting dose of 1 mg/kg. The treatment with prednisolone resulted in a complete remission that lasted up to two years of follow up. This case highlights the variable expression of sarcoidosis, which should be considered in the management of such disease.