Critically ill neonates are at risk for acute kidney injury (AKI) and associated complications including fluid overload, longer mechanical ventilation time, increased hospital length of stay, and death. While the general approach to the evaluation and management of AKI in babies is similar to that in older children and adults, optimal care of these fragile patients requires an understanding of the aspects of neonatal physiology and disease unique to this patient group. Neonatal-specific high risk-conditions include extreme prematurity, perinatal asphyxia, necrotizing enterocolitis, and hemodynamically significant patent ductus arteriosus. In addition, neonates exhibit a renal physiology that changes as they transition from intra- to extra-uterine life, one that varies also between term and preterm infants, and creates challenges for interpretation of kidney function biomarkers such as serum creatinine and urine output. Patient heterogeneity in terms of gestational age and size poses additional challenges for the standardization of AKI definitions and monitoring as well as for provision of kidney support therapy when needed. Medical management has historically been the cornerstone of therapy due to technical barriers associated with providing kidney support therapy to these small patients, but advances in technology are reshaping the indications, timing, and risks and benefits of dialysis provision in this setting. New research is highlighting the interplay between AKI and other organs, especially the lungs and brain. The risk for chronic kidney disease, especially in extremely premature infants with and without a history of AKI, is becoming increasingly clear and highlights the need for long-term follow-up.
