[Guidelines for diagnosis and follow-up of children and adolescents with portal hypertension].

Portal hypertension is a complex syndrome caused by increased resistance to the splachnic venous flow at the portal vein level, with a hyperdynamic systemic circulation characterized by peripheral vasodilation and high cardiac output. Portal flow can be obstructed at prehepatic (¨normal liver¨), intrahepatic (as in cirrhosis), or post-hepatic level (as in Budd-Chiari syndrome). In pediatric patients, prehepatic and intrahepatic causes are almost equally distributed (nearly 50% each). Clinical presentation and individual impact are heterogeneous, but in each case, it is the expression of a worsening condition and the need to solve the problem, either by treating its consequences or (ideally) its causes.