[Portal hypertension].

Portal hypertension is a frequent and clinically important complication of chronic liver diseases. Beside bleeding episodes from oesophageal and gastric varices, ascites formation and hepatic encephalopathy are sequelae of the haemodynamic changes seen under chronic portal hypertensive conditions. These are characterized by a systemic vasodilatation and a subsequent hyperdynamic circulation, leading to an increased arterial inflow into the splanchnic vascular bed. This so-called "arterial vasodilatation theory" is crucial for the persistence of portal hypertension even after the opening of decompressing collaterals. Furthermore, these changes are pathophysiologically linked to ascites formation and the development of hepatic encephalopathy. This article briefly discusses the diagnostic and therapeutic procedures in patients with ascites and hepatic encephalopathy. With regard to the diagnosis and treatment of varices and their bleeding, the reader is referred to the article of Eberhard Renner in the same issue of this journal.