Differential diagnosis of prerenal azotemia from acute tubular necrosis and prediction of recovery by Doppler ultrasound

Acute renal failure (ARF) is a life-threatening disease that often causes multiple organ dysfunction, The accurate and rapid diagnosis of the cause of ARF is particularly important for selecting the appropriate therapy, Ultrasound Doppler is a noninvasive diagnostic method that has recently been introduced to clinical nephrology. We report the diagnostic value of Doppler ultrasound in differentiating acute tubular necrosis (ATN) from prerenal azotemia by comparing this study with the fractional excretion of sodium (FENa), renal failure index (RFI), and urinary/serum creatinine (Cr) ratio. Doppler ultrasound was able to differentiate prerenal azotemia from ATN, equivalent to FENa, RFI, and the urinary/serum Or ratio. Doppler ultrasound does not require blood or urine samples and can be performed at the bedside, Of note, Doppler is unaffected by changes in Na or Or in urine or serum after diuretics or hemodialysis, Furthermore, one can predict recovery from ATN by Doppler findings. Thus, we consider Doppler ultrasound an effective diagnostic tool in ARF. (C) 2000 by the National Kidney Foundation, Inc.