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Nephrology
Paediatric Acute Kidney Injury
a report by
Stuart L Goldstein
Associate Professor of Paediatrics, Baylor College of Medicine, and Medical Director, Renal Dialysis Unit and Pheresis Service, Texas Children’s Hospital
Fundamental and extensive research effort has been expended in the did so in the first seven days of intensive care unit (ICU) admission.
area of both paediatric and adult patient acute kidney injury (AKI) in Patients who developed AKI by RIFLE in the first 14 days had increased
the past decade. This investigation has spanned the clinical and Paediatric Risk of Mortality (PRISM II)
6
scores on ICU admission. Failure
translational arenas, focusing on such basic issues as updating to reach RIFLE level in the first seven days of ICU admission resulted in
epidemiology, redefining both the definition of and nomenclature to a 98% negative predictive value of developing AKI after seven days.
classify AKI and searching for markers other than serum creatinine An independent evaluation of pRIFLE revealed similar results, as
(SCr) to identify renal injury before significant metabolic derangement patients with AKI according to pRIFLE had five times higher mortality
occurs. Finally, substantial published study now lends insight into than patients without AKI (25 versus 5%; p<0.05).
7
RIFLE is merely a
optimal methods for AKI management and renal replacement therapy first step in addressing the lack of a uniform AKI definition: RIFLE or
provision. The aim of this article is provide a description of the state of any other proposed AKI classification systems requires multicentre
the art in paediatric AKI diagnosis and management by highlighting collaborative validation to allow broad applicability across disease
recent significant clinical and research progress. spectra and minimise single-centre effects.
How Should Acute Kidney Injury Be Defined? Urinary Biomarkers of Acute Kidney Injury –
Despite the significant morbidity and mortality associated with AKI, The Search for ‘Renal Troponin I’
over 30 definitions exist in the published literature.
1
Reasons for the As noted in the previous section, small increases in SCr may reflect
varied definitions include the specific patient populations studied and significant renal insult and be associated with significant morbidity in
the outcome measure of interest (e.g. rise in creatinine versus need for patients with AKI. Intensive investigation has led to the identification of
renal replacement therapy). The belief that since renal replacement several potential urinary biomarkers that may herald AKI prior to a rise
therapy provision is ubiquitous and standard, and so patients never die in SCr. Paediatric patients comprise an important population for study,
‘from’ their AKI but rather ‘with’ AKI, may have led us to believe that since they usually do not have significant co-morbidities such as
precise terminology and staging of AKI is unnecessary. hypertension, atherosclerosis and diabetes that affect kidneys in adults.
Lack of a uniform and multidimensional AKI classification system has Infants with congenital heart disease undergoing corrective surgery
led to the inability to generalise single study results.
2
Furthermore, provide an informative population for the study of putative urinary AKI
since most AKI definitions are based on an SCr rise, lack of uniform biomarkers, since the time of renal ischaemia (i.e. cardiopulmonary
definition may result in lack of recognition of significant renal injury bypass [CPB]) is known and these children can be studied prospectively
and delay in treatment. Chertow recently demonstrated that ‘small’ for development of AKI. Mishra and colleagues assessed
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the incidence
increases in SCr of 0.3mg/dl could be associated with increased patient of AKI in this population and assayed urine for appearance of
mortality, even when outcome is controlled for significant patient neutrophil gelatinase-associated lipocalin (NGAL) to determine
co-morbidity.
3
Paediatric data from our centre showed that a 0.3mg/dl whether increased urinary NGAL concentration after CPB preceded
or greater SCr rise in 60 paediatric patients with acute decompensated and predicted increases in SCr. Twenty of 71 patients developed AKI
heart failure was associated with a seven-fold increased mortality risk.
4
(defined as a doubling of SCr). Urinary NGAL increased at least 50-fold
and preceded SCr rise by at least 24 hours in all patients who
These data argue for a graded AKI classification system that can developed AKI.
identify patients at risk of developing significant renal insult and
metabolic disturbance. The Acute Dialysis Quality Initiative (ADQI)
Stuart L Goldstein is an Associate Professor of Paediatrics
(www.adqi.net) recently proposed
1
a multidimensional system termed
at Baylor College of Medicine and Medical Director of the
the RIFLE criteria (risk, injury, failure, loss and end-stage renal disease
Renal Dialysis Unit/Pheresis Service at Texas Children's
[ESRD]), which classifies the degree of renal insult by changes in SCr
Hospital in Houston. The primary aims of his clinical
research have been to develop methods to optimise the
and/or the duration of oliguria. RIFLE is an empirical classification care of children with end-stage renal disease (ESRD) and
system that has only recently undergone clinical validation. We
acute kidney injury (AKI), especially with respect to
haemodialysis and continuous renal replacement therapy
prospectively studied
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critically ill paediatric patients receiving
(CRRT), respectively. He is actively involved in the
mechanical ventilation and used paediatric modified RIFLE (pRIFLE) evaluation of AKI classification systems and urinary biomarkers in children with AKI. He is
criteria to describe the pattern of paediatric AKI and determine
the Founder and Principal Investigator of the Prospective Pediatric CRRT Registry Group, a
12-centre collaborative effort designed to study all aspects of paediatric CRRT.
whether RIFLE provides sufficient sensitivity and specificity in the
clinical setting. The majority of patients who developed AKI by RIFLE
E: stuartg@bcm.edu
© TOUCH BRIEFINGS 2008 23
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