Hepatic vena cava syndrome: New concept of pathogenesis.

Hepatic vena cava syndrome, also known as membranous obstruction of inferior vena cava (IVC), was considered a rare congenital disease and classified under Budd-Chiari syndrome. It is now recognized as a bacterial infection-induced disease related to poor hygiene. Localized thrombophlebitis of the IVC at the site close to hepatic vein outlets is the initial lesion which converts on resolution into stenosis or complete obstruction, the circulatory equilibrium being maintained by development of cavo-caval collateral anastomosis. These changes persist for the rest of the patient's life. The patient remains asymptomatic for a variable period until acute exacerbations occur, precipitated by bacterial infection, resulting in deposition of thrombi at the site of the lesion and endophlebitis in intrahepatic veins. Large thrombus close to hepatic vein outlets results in ascites from hepatic venous outflow obstruction, which is followed by development of venocentric cirrhosis. Endophlebitis of intrahepatic veins results in ischemic liver damage and development of segmental stenosis or membrane. Acute exacerbations are recognized clinically as intermittent jaundice and/or elevation of aminotransferase or ascites associated with neutrophil leukocytosis and elevation of C-reactive protein; sonologically, they are recognized as the presence of thrombi of different ages in IVC and thrombosis of intrahepatic veins. Development of liver cirrhosis and hepatocellular carcinoma is related to severity or frequency of acute exacerbations and not to duration or type of caval obstruction. Hepatic vena cava syndrome is a common co-morbid condition with other liver diseases in developing countries and it should be considered in differential diagnosis in patient with intermittent elevation serum bilirubin and or aminotransferase or development of ascites and cirrhosis.