Acute Kidney Injury - Part I

Acute renal failure (ARF) has been defined as a syndrome in which an abrupt decrease in renal function produces retention of nitrogenous waste products. Translating this abstract description into a clinically useful, accurate, and widely accepted definition has been challenging, in large part because of the focus on serum creatinine concentration, which is easily obtained but has the inherent limitation of poor detection of rapid or subtle, but clinically important, changes in the glomerular filtration rate (GFR). In recent years, therefore, the term acute kidney injury (AKI) has replaced ARF because AKI denotes the entire clinical spectrum from mild increases in serum creatinine to overt renal failure. AKI is defined by the Risk-Injury-Failure-Loss-ESRD (RIFLE) criteria, based on serum creatinine concentration and urine flow rate. The Acute Kidney Injury Network (AKIN) subsequently modified the definition further and divided AKI into three stages. This chapter includes discussions of the etiology and diagnosis of AKI in hospitalized patients and community-acquired AKI. The specific causes, management, and complications of AKI are also discussed. Figures illustrate the pathophysiologic classification of AKI and the effect of hyperkalemia on cardiac conduction—electrocardiogram (ECG) changes. A worksheet for following patients with AKI is provided.  This review contains 3 figures, 20 tables, and 46 references. Keywords:Acute kidney injury, dialysis, contrast, rhabdomyolysis, nephropathy, urinalysis, multiple myeloma, ethylene glycol, sepsis, hepatorenal syndrome