Definitions of acute renal failure range from severe (i.e. requiring dialysis) to slight increases in serum creatinine concentration (e.g. of 44.2 micromol/L). In the absence of a universal definition, acute renal failure is often defined as a significant deterioration in renal function occurring over hours or days. There may be no symptoms or signs, but oliguria (urine volume less than 400 mL/24 h) is common. There is an accumulation of fluid and nitrogenous waste products demonstrated by a rise in blood urea and creatinine. → ...