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Kidney dysfunction is very frequent in patients with advanced liver disease and/or portal hypertension and is independently associated with decreased survival.1,2
Kidney dysfunction may be acute, chronic, and acute-on-chronic. A major difficulty in general medical and surgical settings is to determine the real baseline renal function.
Kidney dysfunction may be due to structural damage, to hemodynamic alterations related to portal hypertension, or to both.
Recognition of renal dysfunction in patients with liver disease and understanding the pathophysiologic mechanism is essential because:
Renal dysfunction is associated with poor outcomes.
Reversible causes of renal dysfunction can be identified and treated.
Renal dysfunction may be the first marker of a multiorgan dysfunction, as in sepsis and cardiocirculatory hepatorenal disease.
Renal function is usually assessed by measurement of serum creatinine. Nevertheless, serum creatinine is an inaccurate marker of glomerular filtration rate (GFR) in the setting of advanced liver disease and/or portal hypertension.
Accurate quantitative assessment of renal function is not easy, may be cumbersome, and most of the time is not strictly necessary.
However, accurate assessment of renal function may be crucial to:
Identify patients whose renal function is expected to improve after transplantation.
Recognize patients necessitating a simultaneous kidney and liver transplantation.
Assure an equitable allocation of organs for transplantation.
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An organ failure is a pathologic situation in which the organ is no longer able to achieve some or all of its physiologic functions. Classically, loss of renal function—but also any kind of kidney damage—was called renal failure and it was classified as acute or chronic. A huge body of research and decades of clinical experience led to a growing insight in the normal physiology of the kidneys and the pathologic processes that affect their function and/or structure. As knowledge advances, so do concepts and definitions. A more precise nomenclature may reflect a deeper understanding of the normal physiology and the pathophysiologic process.
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In liver diseases, the difference between hepatitis and liver failure appears to be evident for most physicians. Cellular damage, inflammation, and cellular death are quite different from loss of organ function. In kidney diseases, the term renal failure has been broadly used over the decades to describe a large spectrum of pathologies, from a slight decrease in GFR to end-stage renal disease.
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The terms renal insufficiency and renal failure are currently reserved for end-stage renal disease, warranting a substitution of renal functions (dialysis or transplantation). The term acute kidney injury (AKI) refers to a new-onset decrease in GFR and/or urine output. During AKI, overt loss of renal functions may occur, especially in the presence of oliguria. Otherwise, renal capacity to regulate the volume and composition of body fluids may remain preserved. From a prognostic point of view, most cases of AKI are reversible, and small percentage will progress to end-stage renal disease.
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The occurrence of AKI can be due to a specific renal insult but also the expression ...