Neonatal acute kidney injury: diagnosis, recognition, and prevention

Acute kidney injury (AKI) occurs in approximately one-third of babies treated in a neonatal intensive care unit. The establishment of consensus standardized definitions has improved clinical recognition and research into neonatal AKI. Neonatal AKI is now recognized for its independent associations with increased morbidity and neonatal intensive care unit mortality. Current definitions use increasing serum creatinine and/or decreasing urine output to diagnose AKI; however, these biomarkers reflect organ dysfunction long after injury has begun. Furthermore, they are impractical and insensitive metrics of kidney function in neonates, particularly in preterm neonates or the first weeks of life, when the risk is greatest. Given the lack of symptoms and limitations of current criteria, risk recognition and stratification are imperative to focus AKI stewardship. Urinary biomarkers (such as neutrophil gelatinase-associated lipocalin), which have demonstrated some challenges in adult studies, appear more promising in their capacity to reliably detect early pediatric and neonatal AKI. Even without novel biomarkers, numerous multidisciplinary AKI education and stewardship programs have demonstrated capacity to substantially reduce risk and incidence of AKI, particularly those focusing on the risk represented by nephrotoxic medication exposure. This narrative review reflects on the evolution of neonatal AKI definitions and how the improved epidemiologic understanding of the condition has been leveraged to drive quality improvement initiatives, development of risk stratification tools, improved diagnostics, and potential preventative therapies. Future integration of this burgeoning body of collaborative research will expedite accurate neonatal AKI diagnosis, while scaffolding kidney health surveillance into follow-up for the improvement of short- and long-term outcomes for these most vulnerable patients.