[Contribution of renal biopsy to the diagnosis and treatment of acute kidney failure].

The mortality rate of acute renal failure is still high, about 50%. About 10% of the survivors have chronic renal failure, sometimes requiring dialysis. The course of some of these cases can be improved by appropriate therapeutic measures, if they are undertaken early. Early identification of these lesions is therefore mandatory. The clinical diagnosis is often difficult: 1. rare atypical forms of acute tubular necrosis, with renal or extrarenal signs, may lead to renal biopsy; 2. vascular and glomerular disease are most often recognized clinically (sometimes misdiagnosed), but the histological type (and therefore the appropriate treatment) cannot be determined; 3. acute interstitial nephritis is rarely diagnosed clinically and the nature of the infiltrate remains unknown. In certain cases of acute renal failure, the contribution of early renal biopsy to the etiological diagnosis and to prognosis and therapy is obvious. In acute renal failure, renal biopsy should be considered early in a rather limited number of patients (about 20%), everytime the diagnosis of tubular necrosis is doubtful, especially in acute renal failure associated with persistent infection, in order to guide the therapy.