Acquired multifactorial condition caused by postsinusoidal hepatic venous outflow obstruction. The cause of the obstruction may be related to hypercoagulability of the blood, infections, cancer, and other conditions, which may be acute, chronic, or asymptomatic.
Chiari Syndrome; Venoocclusive Disease of the Liver.
First commented on by the English internist George Budd (1808-1882) in 1846, but it was the Austrian pathologist Hans Chiari (1851-1916) who was the first to accurately describe the disease in 1899.
The incidence is quite variable and depends on the geographical location. While it is in the range of 1:2,5000,000 per year in the Western World, it can be as high as 1:100,000 per year in some Asian countries (eg, China, India, Nepal). In Western countries, isolated hepatic vein obstruction dominates and females are more commonly affected than males with a median age at presentation between 35 and 38 years. In Asia, obstruction of the inferior vena cava (IVC) with or without involvement of the hepatic veins is the predominant cause of BCS and males are more often affected than females with a median age 45 years at presentation.
No genetic basis has been described. Familial cases have been described, but are most likely due to common underlying environmental and/or genetic risk factors (eg, autosomal dominant inherited factor V Leiden thrombophilia).
The symptoms result from decreased hepatic venous outflow. Flow obstruction results in portal hypertension and hepatocellular damage. Liver cirrhosis and portal hypertension eventually develop. The 2-year mortality rate in untreated disease is around 20 to 40%.
The most important diagnostic tool is ultrasonography with the pathognomonic feature of “undetectable” (or small residual lumen) hepatic veins with absent or reverse flow by Doppler ultrasound, dilated intrahepatic collaterals, compressed IVC, enlargement of the caudate liver lobe and diminished/absent portal venous, hepatic, and inferior vena cava blood flow. Drainage of collateral vessels into the subcapsular or intercostal veins is considered a highly sensitive and specific finding of BCS. Alternatively, hepatic venography, CT, or MRI (particularly 3-dimensional contrast-enhanced MR angiography) may be used.
BCS is the result of a partial or complete venous obstruction at any level from the small hepatic veins to the junction of the IVC with the right atrium. Sinusoidal obstruction syndrome and cardiac or pericardial diseases are not included in this definition of BCS. The etiology is multifactorial and often no causative factor can be identified. Risk factors include myeloproliferative diseases (in up to 50% of patients; eg, polycythemia rubra vera, essential thrombocytosis, chronic myeloid leukemia, agnogenic myeloid metaplasia, and primary myelofibrosis), paroxysmal nocturnal hemoglobinuria, thrombophilia (including factor V Leiden), ...