Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Key Features +++ Essentials of Diagnosis ++ Sudden inability to excrete urine of sufficient quantity or composition to maintain body fluid homeostasis Explanations include quickly reversible problems such as dehydration or urinary tract obstruction, as well as new-onset renal disease (eg, acute glomerulonephritis), drug-related toxic nephropathies, or renal ischemia Renal ischemia is suspected when significant hemodynamic instability or other circumstances result in decreased renal perfusion +++ General Considerations ++ Classifying acute kidney injury as prerenal, renal, and postrenal is helpful in determining whether an immediately reversible cause is present Prerenal causes Compromised renal perfusion is most common cause of acute decreased renal function in children Usually secondary to true intravascular volume depletion or a decrease in effective circulating volume, as may be seen in cardiac failure, cirrhosis, or nephrotic syndrome Renal causes Include acute glomerulonephritides, hemolytic-uremic syndrome, acute interstitial nephritis, and nephrotoxic injury Diagnosis of acute tubular necrosis is reserved for those cases in which renal ischemic insult is believed to be the likely cause; should be considered when Correction of prerenal or postrenal problems does not improve renal function There is no evidence of de novo renal disease Postrenal causes Usually found in newborns with urologic anatomic abnormalities Accompanied by varying degrees of kidney disease Possibility of acute urinary tract obstruction in acute kidney injury, especially in the setting of anuria of acute onset, should be considered +++ Clinical Findings ++ Oliguria with subsequent variable rise in serum creatinine and BUN is hallmark of acute kidney injury Entities that can be quickly addressed and corrected, for example, intravascular volume depletion or urinary tract obstruction, should be considered first +++ Diagnosis ++ Urine osmolality and sodium concentration should be interpreted in light of the child's age-related capacity for these parameters (eg, newborns have limited urinary concentrating capacity and excrete more sodium than older children) Urine osmolality Prerenal failure: > 500 Acute tubular necrosis: < 350 Urine-specific gravity Prerenal failure: > 1.020 Acute tubular necrosis: ~ 1.010 Urine sodium Prerenal failure: < 20 mEq/L Acute tubular necrosis: > 40 mEq/L Fractional excretion of sodium Prerenal failure: < 1% Acute tubular necrosis: > 3% Ratio of urine creatinine to plasma creatinine Prerenal failure: > 40:1 Acute tubular necrosis: < 20:1 Ratio of blood urea nitrogen (BUN) to plasma creatinine Prerenal failure: > 20:1 Acute tubular necrosis: < 10–15 +++ Treatment +++ Nonpharmacologic ++ Prerenal and postrenal factors should be excluded and rectified Normal circulating volume should be maintained and normal blood pressure and cardiac performance established with appropriate fluid or vasopressor support Placement of a Foley bladder catheter can aid in timely measurement of output Measurement of central venous pressure may be indicated Routine assessment of weight is helpful to assess fluid balance +++ Pharmacologic ++ Furosemide (1–5 mg/kg, per dose, intravenously, maximum ... Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth