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 m ultiple organ dysfunction, The accurate and rapid diagnosis of the cause of ARF is particularly important for selecting the appropriate therapy, Ultra sound Doppler is a noninvasive diagnostic method that has recently been int roduced to clinical nephrology. We report the diagnostic value of Doppler u ltrasound in differentiating acute tubular necrosis (ATN) from prerenal azo temia by comparing this study with the fractional excretion of sodium (FENa ), renal failure index (RFI), and urinary/serum creatinine (Cr) ratio. Dopp ler ultrasound was able to differentiate prerenal azotemia from ATN, equiva lent 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 b y Doppler findings. Thus, we consider Doppler ultrasound an effective diagn ostic tool in ARF. (C) 2000 by the National Kidney Foundation, Inc.