Pathophysiology and Clinical Work-Up of Acute Kidney Injury.

Acute kidney injury (AKI), also known in the past as acute renal failure, is a syndrome characterized by the rapid loss of kidney excretory function. It is usually diagnosed by the accumulation of end products of nitrogen metabolism (urea and creatinine) or decreased urine output or both. AKI is the clinical consequence of several disorders that acutely affect the kidney, causing electrolytes and acid-base imbalance, hyperhydration and loss of depurative function. AKI is common in critical care patients in whom it is often secondary to extrarenal events. No specific therapies can attenuate AKI or accelerate renal function recovery; thus, the only treatment is supportive. New diagnostic techniques such as renal biomarkers might improve early diagnosis. Also ultrasonography helps nephrologists in AKI diagnosis, in order to describe and follow kidney alterations and find possible causes of AKI. Renal replacement therapy is a life-saving treatment if AKI is severe. If patients survive to AKI, and did not have previous chronic kidney disease (CKD), they typically recover to dialysis independence. However, evidence suggests that patients who have had AKI are at increased risk of subsequent CKD.