Acute kidney injury: current concepts and new insights

BACKGROUND: Acute kidney injury, which was previously named as acute renal failure, is a complex clinical disorder and continues to be associated with poor outcomes. It is frequently seen in hospitalized patients, especially in critically ill patients. The primary causes of acute kidney injury are divided into three categories: prerenal, intrinsic renal and postrenal. The definition and staging of acute kidney injury are mainly based on the risk, injury, failure, loss, end-stage kidney disease (RIFLE) criteria and the acute kidney injury network (AKIN) criteria, which have previously been defined. However the clinical utility of these criteria is still uncertain. Several biomarkers such as Cystatin C and neutrophil gelatinase-associated lipocalin have been suggested for the diagnosis, severity classification and most importantly, the modification of outcome in acute kidney injury. METHODS: Current literature on the definition, biomarkers, management and epidemiology of acute kidney injury was reviewed by searching keywords in Medline and PubMed databases. RESULTS: The epidemiology, pathophysiology and diagnosis of acute kidney injury were discussed. The clinical implications of novel biomarkers and management of acute kidney injury were also discussed. CONCLUSIONS: The current definitions of acute kidney injury are based on the RIFLE, AKIN and KDIGO criteria. Although these criteria have been widely validated, some of limitations are still remain. Since acute kidney injury is common and harmful, all preventive measures should be taken to avoid its occurrence. Currently, there is no a definitive role for novel biomarkers.