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Acute kidney injury in children: Clinical features, etiology, evaluation, and diagnosis

Prasad Devarajan, MD
Section Editor
Tej K Mattoo, MD, DCH, FRCP
Deputy Editor
Melanie S Kim, MD


Acute kidney injury (AKI) is defined as the abrupt loss of kidney function that results in a decline in glomerular filtration rate (GFR), retention of urea and other nitrogenous waste products, and dysregulation of extracellular volume and electrolytes. The term AKI has largely replaced acute renal failure (ARF), as it more clearly defines renal dysfunction as a continuum rather than a discrete finding of failed kidney function. Pediatric AKI presents with a wide range of clinical manifestations from a minimal elevation in serum creatinine to anuric renal failure, arises from multiple causes, and occurs in a variety of clinical settings [1-7].

An overview of the causes, clinical presentation, and diagnosis of AKI in children will be presented here. The prevention, management, and outcomes of AKI in children and the approach to AKI in newborns are presented separately. (See "Prevention and management of acute kidney injury (acute renal failure) in children" and "Acute kidney injury (acute renal failure) in the newborn".)


Acute kidney injury (AKI) is defined as a decrease in glomerular filtration rate (GFR), which traditionally is manifested by an elevated or a rise in serum creatinine from baseline. However, serum creatinine is often a delayed and imprecise test as it reflects GFR in individuals at steady state with stable kidney function, and does not accurately reflect the GFR in a patient whose renal function is changing. For example, a child in the early stages of severe AKI with a markedly reduced GFR may have a relatively normal or slightly elevated creatinine, as there has not been sufficient time for creatinine accumulation. In addition, creatinine is removed by dialysis, and it is not possible to assess renal function using serum creatinine once dialysis is initiated. Despite these limitations, elevated or a rise in serum creatinine continues to be the most widely used laboratory finding to make the diagnosis of AKI in children. (See 'Diagnosis' below.)

The inability of serum creatinine to accurately reflect kidney function has been especially problematic for clinical research in pediatric AKI. This has resulted in the use of more than 35 definitions of AKI in clinical studies, ranging from small changes in serum creatinine to dialysis requirement. Because of the lack of a consensus definition, comparisons among studies are difficult, resulting in a wide range of quoted epidemiology, morbidity, and mortality rates in the AKI pediatric literature [8]. The most widely used standardized definitions for pediatric AKI are the pediatric RIFLE (pRIFLE), AKI Network (AKIN), and Kidney Disease Improving Global Outcomes (KDIGO) classifications. (See "Definition of acute kidney injury (acute renal failure)".)

pRIFLE — pRIFLE is a pediatric modification of the adult RIFLE classification and consists of three graded levels of injury (Risk, Injury, and Failure) based upon the magnitude of change in estimated GFR (eg, changes in serum creatinine) or urine output, and two outcome measures (Loss of kidney function and End-stage renal disease) (table 1) [9]. Differences between the adult and pediatric classification include:


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Literature review current through: Sep 2016. | This topic last updated: Sep 21, 2016.
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