Noncirrhotic portal hypertension.

Noncirrhotic portal hypertension represents a heterogeneous group of conditions that have distinct clinical and hemodynamic features that often help distinguish them from cirrhosis. [figure: see text] The sites of portal flow resistance may not be precisely localized to one area of the hepatic lobule and may extend beyond the site where the pathogenetic process began. Even in patients with portal hypertension caused by an increased flow, there may be subsequent development of increased resistance. The prognosis is variable; outcomes are better in patients with presinusoidal portal hypertension. A good understanding of the presentation of the various noncirrhotic conditions that cause portal hypertension will help determine the cause, the site of resistance, and the therapeutic plan. Ascites is not a feature of presinusoidal portal hypertension, whereas it may be the predominant feature in postsinusoidal portal hypertension.