Systemic consequences of acute kidney injury.

PURPOSE OF REVIEW: Acute kidney injury (AKI) is a frequent and serious event associated with a high rate of complications, with an increased risk of progression to multiple organ dysfunction and excessive 'attributable' mortality. AKI affects all physiologic functions and organ systems with interrelated mechanisms, including the 'classical' consequences of the uremic state, the inflammatory nature of AKI per se and resulting systemic effects, the modulating effect of AKI in the presence of an (inflammatory) underlying disease process and the multiple untoward effects induced by renal replacement therapy (RRT) and anticoagulation.

RECENT FINDINGS: A rapidly increasing body of evidence is clarifying these systemic effects that are the reflection of a broad common pathology that ultimately results in an 'augmented' inflammation and impairment of immunocompetence. This includes the release of cytokines and inflammatory mediators, increase in oxidative stress, activation of various immune cells, neutrophil extravasation, generalized endothelial injury, increased vascular permeability and tissue oedema formation.

SUMMARY: These systemic phenomena associated with AKI induce distant organ injury affecting all organ systems with clinically the most relevant effects being exerted on the lungs, the intestines and liver and the heart and predispose the progression to multiple organ dysfunction syndrome and death. Currently available renal replacement therapy modalities are incapable of compensating for these systemic consequences of AKI.