Portal Hypertension

Abstract

Definition

Portal hypertension is a condition of chronically raised pressure in the portal venous system, giving rise to splenomegaly and the development of enlarged collateral venous channels connecting the portal and systemic circulatory systems.

Anatomy

Figure I illustrates the disposition of the main veins of the portal system and indicates the chief sites at which this system communicates with the systemic veins. The presence of a Caput Medusae in cases of intrahepatic obstruction, and its absence in extrahepatic obstruction. is evident from the drawing. Not all of these sites are important clinically or diagnostically, but their total capacity causes a very considerable volume of blood to bypass the liver and be released into the general circulation when the communications are enlarged.