PORTAL HYPERTENSION

Question 1

Overview (4)

Answer 1

• The portal vein is formed by the union of superior mesenteric (from the gut) and splenic vein (from the spleen) and transports blood to the liver
• It accounts for 75% of hepatic vascular inflow; 25% is via the hepatic artery. Blood vessels enter the liver via the hilum (porta hepatis) and blood passes into the hepatic sinusoids via the portal tracts and leaves the liver through the hepatic veins to join the inferior vena cava.
• The normal portal pressure is 5-8mmHg. >10mmHg indicates portal HTN
• The inflow of portal blood to the liver can be partially or completely impeded —> high pressure proximal to the obstruction and the diversion of blood into portosystemic collaterals (e.g. gastroesophageal junction (varices), superficial epigastric veins (caput medusa))

Question 2

Common presenting features (4)

Answer 2

• Gastrointestinal bleeding from esophageal or gastric (less common) varices
• Ascites
• Hepatic encephalopathy
• The only evidence of portal hypertension may be splenomegaly in a patient with clinical signs of chronic liver disease

Question 3

Causes of Portal Hypertension - Prehepatic

Answer 3

(due to blockage of the portal vein before the liver)
- Portal vein thrombosis

Question 4

Causes of Portal Hypertension - Intrahepatic

Answer 4

(due to distortion of the liver architecture)
- Cirrhosis
- Alcoholic hepatitis
- Idiopathic non-cirrhotic
- Schistosomaisis
- Venoocclusive disease

Question 5

Causes of Portal Hypertension - Post-hepatic

Answer 5

(due to venous blockage outside of the liver)
- Budd-Chiari syndrome (thrombosis in hepatic veins)
- Right heart failure
- Constrictive pericarditis
- Inferior vena cava obstruction