Acute Kidney Injury in Children

Acute kidney injury (AKI) is a clinical condition considered to be the consequence of a sudden decrease (>25%) or discontinuation of renal function. The term AKI is used instead of the previous term acute renal failure, because it has been demonstrated that even minor renal lesions may cause far-reaching consequences on human health. Contemporary classifications of AKI (RIFLE and AKIN) are based on the change of serum creatinine and urinary output. In the developed countries, AKI is most often caused by renal ischemia, nephrotoxins and sepsis, rather than a (primary) diffuse renal disease, such as glomerulonephritis, interstitial nephritis, renovascular disorder and thrombotic microangiopathy. The main risk factors for hospital AKI are mechanical ventilation, use of vasoactive drugs, stem cell transplantation and diuretic-resistant hypervolemia. Prerenal and parenchymal AKI (previously known as acute tubular necrosis) jointly account for 2/3 of all AKI causes. Diuresis and serum creatinine concentration are not early diagnostic markers of AKI. Potential early biomarkers of AKI are neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, kidney injury molecule-1 (KIM-1), interleukins 6,8 and 18, and liver-type fatty acid-binding protein (L-FABP). Early detection of kidney impairment, before the increase of serum creatinine, is important for timely initiated therapy and recovery. The goal of AKI treatment is to normalize the fluid and electrolyte status, as well as the correction of acidosis and blood pressure. Since a severe fluid overload resistant to diuretics and inotropic agents is associated with a poor outcome, the initiation of dialysis should not be delayed. The mortality rate of AKI is highest in critically ill children with multiple organ failure and hemodynamically unstable patients.