Thrombosis of the Inferior Vena Cava.

Inferior vena caval obstruction occurs not infrequently. In 1911 Pleasants reviewed 314 published cases of which 68 per cent. were due to thrombosis, I6 per cent. to external pressure and I6 per cent. to invasion by neoplasm. Where it is due to thrombosis this is usually due to spread from veins in the legs and pelvis. In most cases the thrombosis is confined to the lower part of the inferior vena cava, the upper end of the thrombus being below the entrance of the renal veins. It is believed that further extension upwards is prevented by the considerable blood flow from the kidneys. Even if the thrombus extends up to the right auricle it is unusual for the hepatic veins to be obstructed with the development of a BuddChiari syndrome (Harrison et al., 1956). The following case is of interest because of the extent of the thrombosis and the lack of renal or hepatic symptoms.