Nephrology Update: Acute Kidney Injury.

Acute kidney injury (AKI) refers to any acute decrease in glomerular filtration rate, regardless of etiology. Staging of AKI has been recommended to stratify AKI patients according to severity of the condition, based on serum creatinine level and urine output. Classification of AKI into prerenal, intrinsic renal, and postrenal etiologies is helpful in differential diagnosis and management. AKI in hospitalized patients typically occurs due to decreased renal perfusion. Drug-induced, contrast-associated, postoperative, and sepsis-associated AKI also can occur. Clinical assessment of a patient with AKI involves a medical record review, thorough history and physical examination, urinary and blood tests, renal imaging, and, in some instances, renal biopsy. Contrast-induced nephropathy is a common iatrogenic etiology of AKI associated with administration of intravenous iodinated contrast media. Measures to prevent AKI should be taken before administration of intravenous iodinated contrast. AKI can result in many short- and long-term complications, including chronic kidney disease and end-stage renal disease. Appropriate treatment of AKI patients involves management of the underlying etiology, when possible, and use of nondialytic and dialytic therapies.