Acute kidney injury in children: the dawn of a new era

Excerpt

The next series of teaching articles are devoted to acute kidney injury (AKI). AKI, previously known as acute renal failure, represents a significant and devastating problem in clinical medicine. More than 30 definitions of AKI exist in the literature, most of which are based on serum creatinine [1]. Lack of a uniform and multidimensional AKI definition has led to failure to recognize significant renal injury, delays in treatment, and inability to generalize single-study results. A new classification system, using the criteria of risk, injury, failure, loss, and end-stage renal failure (acronym RIFLE), has been proposed to standardize the definition of AKI in adults [1]. The RIFLE criteria aim to standardize the definition of AKI based on changes in serum creatinine from baseline, an abrupt decrease in urine output, as well as the length of renal replacement at later stages. As such, these criteria differ from acute physiological assessment and chronic health evaluation score (APACHE) in the adult population. The RIFLE criteria were shown, in a multinational and multicenter study, to independently predict length of stay, costs, morbidity, and mortality, whereas APACHE score did not in adults with AKI [2]. Pediatric AKI studies are limited. Most studies have been performed in single centers with AKI severe enough to require renal replacement therapy and where the patients selected had a high morbidity and mortality rate [3]. More recently, smaller rises in serum creatinine in children have been shown to be associated with a significant risk of mortality [4]. In 2007, a modified pediatric RIFLE (pRIFLE) score (Table 1) was introduced and was shown to predict increased costs, length of stay, mortality, and the need for renal replacement therapy in pediatric patients in the intensive care unit setting [5] and subsequently confirmed by an independent group [6]. With the establishment of pRIFLE, exciting multicenter prospective studies have begun, such as with the Prospective Pediatric Continuous Renal Replacement Therapy Registry Group. One of the early important findings is that worsening fluid overload is an independent risk factor for mortality, irrespective of severity of illness by acute physiological scores such as PRISM, which does not take serum creatinine and urine output into account [7]. These recent studies marked very significant developments in the field of AKI in children. It is therefore very timely to introduce an educational series on AKI in this journal. …