[Kidney involvement in liver diseases. Pathophysiology and clinical course]

Renal disorders complicating liver disease are a frequent finding. Extrahepatic causes like intoxications and circulatory dysfunction or diseases that simultaneously affect both the liver and the kidney, like multisystem or viral diseases (hepatitis B) have to be differentiated from clinical entities in which, like in liver cirrhosis or in fulminant hepatitis, the manifestation of renal disease has to be understood as a consequence of the hepatic disorders. Functional disturbances like the increases in tubular sodium reabsorption or the hepatorenal syndrome have been thoroughly investigate because of their clinical importance. Substantial research dealing with the consequences of the increased intrahepatic vascular resistance on systemic and renal hemodynamics and with vasoactive substances, either arising from the liver or accumulating due to poor inactivation by the liver, have led - in the last years - to a better understanding of the pathophysiology of renal involvement in liver disease. However, the exact pathophysiologic role of factors like the effective blood volume, the sympathoadrenergic tonus, the activation of the renin-angiotensin-aldosterone system, changes of kinin activity or in prostaglandin release and the accumulation of "false" neurotransmitters and endotoxins still remains to be established.