Perinatal asphyxia is the most common cause of AKI in newborns, which results mostly from impaired renal perfusion. The accurate diagnosis of neonatal AKI, irrespective of the cause, relies on suboptimal methods such as identification of rising serum creatinine, decreased urinary output and glomerular filtration rate.
This fact hampers not only the early documentation of AKI but also its management. So, there has been interest in developing novel AKI biomarkers that may allow the institution of earlier, and therefore more effective, renoprotective therapies; one such marker is, including urinary and serum neutrophil gelatinase-associated lipocalin (NGAL)
The aim of this study was to evaluate the value of serum and urinary NGAL measurement as an early predictor of acute kidney injury in asphyxiated neonates
Our study was a comparative cross sectional study, carried on 60 full term neonates divided into 2 groups: cases group included 40 full term neonates with a provisional diagnosis of perinatal asphyxia based on the criteria of American Academy of Pediatrics (American Academy of Pediatrics, 1996). Their mean gestational age was 37.85 ± 1 weeks and mean birth weight was 3133.8 ± 457.8 gm. The control group included 20 healthy full term neonates. Their mean gestational age was 37.95 ± 1 weeks and mean birth weight was 3242.5 ± 407 gm.
All patients were subjected to complete history taking, full clinical examination and laboratory investigations including CBC, CRP, blood glucose, serum electrolytes, BUN, serum creatinine, serum & urinary NGAL were measured since the first 24hrs of life and cases were followed up clinically and laboratory
In our study, there was no statistical significant between cases and control groups regarding demographic characteristics (GA, BW, Sex, mode of delivery), also no differences were found among subgroups of asphyxiated neonates and controls regarding demographic – perinatal characteristics
In our study, 55% of the asphyxiated neonates developed acute kidney injury (AKI) (as it was defined by serum creatinine). So cases were subsequently categorized into "asphyxia AKI subgroup "and "asphyxia no - AKI subgroup ".
Our study showed that both serum creatinine and BUN were significantly higher in cases group than control group
In addition, sodium levels, calcium levels, glucose levels, HB% levels, platelets count were significantly lower in asphyxiated neonates as compared to controls and significantly lower in asphyxia AKI - subgroup compared to asphyxia no – AKI subgroup. On the other hand, potassium levels were significantly higher in asphyxiated neonates as compared to controls and significantly higher in asphyxia AKI - subgroup as compared to asphyxia no – AKI subgroup.
Control group (n=20) had a median serum NGAL level of (46 ng/ml) with IQ range (39 – 56 ) ng/ml and a median urinary NGAL level of (9 ng/ml) with IQ range (6 – 11 ) ng/ml there were no statistical significant as regards sex or mode of delivery.
There was no significant correlation between serum and urinary NGAL on one hand and gestational age and birth weight in the control group on the other hand.
Serum and urinary NGAL obtained in the first 24 hours of life showed significantly higher values in asphyxiated neonates compared to controls, irrespective of whether the asphyxiated neonates had AKI or not ( based on elevation of SCr) which hints at the spectrum of AKI that is being missed when diagnosis is based solely on rising SCr .
Also, within the subgroup of asphyxiated neonates, serum and urinary levels of NGAL were significantly higher in "asphyxia AKI subgroup" than "asphyxia no - AKI subgroup ".
In cases group, there was significant positive correlation between serum and urinary NGAL on one hand and creatinine, BUN levels and stage of HIE on the other hand. However, there was no significant correlation between NGAL and Apgar score.
Serum and urinary NGAL was significantly higher in non survivors than survivors.
Serum and urinary NGAL was significantly higher in asphyxiated neonates who needed mechanical ventilation and in asphyxiated neonates who developed convulstions
ROC curves analysis suggested that a serum NGAL cut off value of (144 ng/ml) within the first 24 hours of life in asphyxiated neonates can predict the development of AKI with sensitivity of 95% , specificity of 94%, positive predictive value of 95% and negative predictive value of 94%.
While urinary NGAL can predict acute kidney injury (AKI) at cutoff point of (18 ng/ml) with sensitivity of 95%, specificity of 94%, positive predictive value of 95% and negative predictive value of 94%. |
