Acute interstitial nephritis is a relevant cause of acute renal failure. Drugs are the predominant cause, followed by infections and idiopathic lesions. Acute interstitial nephritis as a form of hypersensitivity reaction is an uncommon manifestation in the setting of human parasitic infections. We present a case of acute interstitial nephritis in association with Giardia infection in a 54-year-old woman who developed an impairment of renal function after a prolonged period of slight fever and diarrhea. After an attempt to recover renal impairment by vigorous rehydratation, because of the unclear origin of the persisting renal failure, a percutaneous renal biopsy was performed and a diagnosis of severe acute interstitial nephritis was made. Steroid therapy was started and after six weeks, renal function had completely recovered. In cases of unexplained renal failure in patients affected by parasitic infections, interstitial nephritis should be considered and it is our opinion that a renal biopsy should be always performed.
Keywords: acute interstitial nephritis; acute renal failure; infections..