Acute renal failure is defined as a rapid decrease in the glomerular filtration rate, occurring over a period of minutes to days. Because the rate of production of metabolic waste exceeds the rate of renal excretion in this circumstance, serum concentrations of markers of renal function, such as urea and creatinine, rise. The causes of acute renal failure are classically divided into three categories: prerenal, postrenal (or obstructive), and intrinsic. Prerenal azotemia is considered a functional response to renal hypoperfusion, in which renal structure and microstructure are preserved. Postrenal azotemia — obstruction of the urinary tract — is initially accompanied . . . Join discussion...