Portal Hypertension

Basics

Description

  • Definition of portal hypertension (P-HTN): elevation of portal pressure (PP) >5 mm Hg
    • Risk of developing complications occurs with “clinically significant P-HTN”: PP >10 mm Hg
    • Significant risk of bleeding from esophageal varices (EV) with PP >12 mm Hg
  • May be pre-, intra-, or posthepatic in origin
  • A major cause of morbidity and mortality in children with chronic liver disease

Pathophysiology

  • P-HTN is secondary to both increases in portal resistance and portal blood flow:
    • Other contributing factors include hyperdynamic circulation, expanded intravascular volume, systemic arteriolar vasodilatation, decreased splanchnic arteriolar tone, and humoral factors (i.e., nitric oxide).
  • Portosystemic collaterals develop to decompress the high PPs, leading to a number of sequelae, all with high morbidity and mortality risks, including:
    • Variceal hemorrhage
    • Splenomegaly/hypersplenism
    • Ascites
    • Spontaneous bacterial peritonitis
    • Hepatorenal syndrome
    • Hepatopulmonary syndrome
    • Portopulmonary hypertension
    • Hepatic encephalopathy

Etiology

  • Prehepatic (presinusoidal) causes:
    • Portal vein thrombosis (PVT) with cavernous transformation (increased risk with umbilical vein catheterization, sepsis, dehydration, hypercoagulable state)
    • Splenic vein thrombosis
  • Intrahepatic (sinusoidal) causes:
    • Hepatocellular disorders: cirrhosis (secondary to chronic viral hepatitis [e.g., Hep B, Hep C, etc.], α1-antitrypsin deficiency, autoimmune hepatitis, Wilson disease, glycogen storage disease, tyrosinemia, etc.), schistosomiasis, peliosis hepatitis, vitamin A toxicity
    • Biliary tract disorders: cirrhosis (secondary to biliary atresia, intrahepatic cholestasis syndromes, primary sclerosing cholangitis, cystic fibrosis, etc.), ductal plate malformation/congenital hepatic fibrosis, choledochal cyst
  • Posthepatic (postsinusoidal) causes:
    • Budd-Chiari syndrome: occlusion of suprahepatic inferior vena cava or hepatic veins by congenital web, tumor, or thrombus
    • Congestive hepatopathy (cardiac: right-sided heart failure or hypertension, such as post-Fontan procedure; pulmonary hypertension)
    • Sinusoidal obstruction syndrome (veno-occlusive disease of hepatic sinusoids and terminal venules)

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