Budd-Chiari syndrome (BCS) was identified by Budd and Chiari in the mid 1890’s. It is a condition resulting from the obstruction of hepatic venous outflow (veins carrying blood from the liver). The most common cause in western countries is thrombosis (blood clot). In South-East Asian and Middle Eastern countries, mass lesions and webs in the major hepatic veins are more characteristic.
How does blood flow to and from the liver work?
With an average through-flow of 1.7 litres per minute, your liver normally receives 70 to 80 per cent of its blood from the portal vein. The rest of the blood flow is obtained from the hepatic artery. The blood mixes together and is collected in small venules (small blood vessels that join to become veins) within the liver lobes. From there it is circulated to progressively larger veins, which ultimately become the major hepatic veins.
Most people have two groups of hepatic veins:
- An upper group consisting of three large veins.
- A lower group of generally smaller veins.
Between them, these veins drain the blood from your liver via the inferior vena cava (the large central vein passing through the liver on course from the abdomen back to the heart).
BCS is an interruption of this blood flow from the liver involving a blockage in one or more veins in either the upper or lower group. Where thrombosis occurs it may be partial or affect only some of the hepatic veins, which allows for compensated liver function and an absence of symptoms.
BCS may present as an acute condition which progresses rapidly with abdominal pain (in the upper right quadrant), ascites (fluid in the abdomen) and hepatomegaly (an enlarged and distended liver due to severe venous congestion). Alternatively, BSC may develop gradually over a period of months.