Acute Kidney Injury Based on Neutrophil Gelatinase-Associated Lipocalcin (NGAL) in a Pediatric Intensive Care Unit of Tertiary Care Hospital Karachi, Pakistan

Introduction:

Acute kidney injury (AKI) is complex disorder affecting the millions of children around the world where approximately 46% of critically ill individual developed acute kidney injury every year (1, 2). An annual incidence of 3.3 cases/100,000 children along with hospital mortality rate of up to 25-50% have reported from developed countries (3) This is even high for developing countries, where annual incidence is 30-50% (4, 5). Furthermore, acute kidney injury leads to significant healthcare use, with cost estimated between 8 billion dollars (4). An early diagnosis is the key to prevent morbidity and mortality related to AKI.

The diagnosis of AKI depends upon elevated serum creatinine level or decrease in urine output . Early detection of AKI is essential. The currently use creatinine clearance (CrCl) is calculated through Schwartz formula. The level of serum creatinine is poor marker for early diagnosis. Because it varies with age, gender, hydration and muscle mass and metabolism. Creatinine never rise until >50% of renal function lost, amount of tubular secretion overestimate at lower GFR, and in acute changes in GFR. During acute changes of GFR in AKI, serum creatinine doesn't accurately depict kidney function until steady state equilibrium has been achieved, which may require several days. There are some biomarker, with high sensitivity and specificity, which can be used as a tool for early detection of AKI, and prevent the burden of mortality and morbidity in intensive care unit (6, 7). Neutrophil gelatinase-associated Lipocalcin (NGAL) recently identified as one of robust marker in AKI (8). Several published reports that plasma NGA is raised in acute kidney injury before rise in serum creatinine (9). A Study conducted by Mishra et al, in US showed that the 2 hours sensitivity is 70% and specificity 94% for NGAL to predict AKI (10). A developed country data showed 84% and 79% sensitivity , and 96% and 90% specificity of NGAL to predict the AKI (2, 11) , (see Annexure 1) . However, there is scarce of information available as plasma NGAL is an early diagnostic marker from Pakistan.

Rationale:

We know that serum creatinine is a gold standard for diagnosis of AKI it is cheaper test to diagnose , but it rises after 1 to 3 days of injury . However, NGAL is a relatively costly test but an emerging biomarker in identifying AKI at an early stages, which may in future help us in promptly instituting reno-protective interventions like avoidance of nephrotoxic exposure and contrast agents, maintenance of euvolemia and perfusion pressure which will not only preventing kidney from further failing, decrease the use of very expensive and complicated renal supportive therapy like continuous renal replacement therapy (CRRT) as well as in decreasing morbidity and mortality related to AKI.