Acute Kidney Injury: Diagnosis and Management

Acute kidney injury is a clinical syndrome characterized by a rapid decline in glomerular filtration rate and resultant accumulation of metabolic waste products. Acute kidney injury is associated with an increased risk of mortality, cardiovascular events, and progression to chronic kidney disease. Severity of acute kidney injury is classified according to urine output and elevations in creatinine level. Etiologies of acute kidney injury are categorized as prerenal, intrinsic renal, and postrenal. Accurate diagnosis of the underlying cause is key to successful management and includes a focused history and physical examination, serum and urine electrolyte measurements, and renal ultrasonography when risk factors for a postrenal cause are present (e.g., older male with prostatic hypertrophy). General management principles for acute kidney injury include determination of volume status, fluid resuscitation with isotonic crystalloid, treatment of volume overload with diuretics, discontinuation of nephrotoxic medications, and adjustment of prescribed drugs according to renal function. Additional supportive care measures may include optimizing nutritional status and glycemic control. Pharmacist-led quality-improvement programs reduce nephrotoxic exposures and rates of acute kidney injury in the hospital setting. Acute kidney injury care bundles are associated with improved in-hospital mortality rates and reduced risk of progression. Nephrology consultation should be considered when there is inadequate response to supportive treatment and for acute kidney injury without a clear cause, stage 3 or higher acute kidney injury, preexisting stage 4 or higher chronic kidney disease, renal replacement therapy, and other situations requiring subspecialist expertise.