what is acute renal failure characterized by
It is one of the clinical hallmarks of renal failure and has been used as a criterion for diagnosing and staging acute kidney injury, previously referred to as acute renal failure. At onset, oliguria is frequently acute. It is often the earliest sign of impaired renal function and poses a diagnostic and management challenge to the clinician. (See Presentation and Workup.) Not all cases of acute kidney injury are characterized by oliguria. Renal failure that results from nephrotoxic injury, interstitial nephritis, or neonatal asphyxia is frequently of the nonoliguric type, is related to a less severe renal injury, and has a better prognosis.