The Influence of the Spleen on Thoracic Duct Lymph in Schistosomat Hepatic Fibrosis

Abstract

1. Splenectomy was found to cause a marked decrease in the thoracic duct lymph flow and pressure
in patients with schistosomal fibrosis.
2. There was no direct correlation between the drop in thoracic duct lymph flow and the drop in
portal pressure produced by removal of the spleen.
3. The splenic lymphatics were found to be increased in number and distended.
4. In some patients, the splenic lymphatics contained intact red blood cells.
5. Removal of the spleen caused immediate disappearance of red blood cells from thoracic duct
lymph.
The pathogenesis of ascites in schistosomal hepatic fibrosis remains unclear. In a previous
communication from our center, we reported increased flow and pressure in the
thoracic duct of patients with schistosomal hepatic fibrosis where portal hypertension
is characterized by presinusoidal obstruction (7).
In Laennec's cirrhosis, excess thoracic duct lymph originates from both the liver and
extrahepatic portal bed (3, 8, 9). These authors also suggest that, in "early" cases, the
liver is the major source of increased thoracic duct lymph, whereas in "late cases excess
extrahepatic portal lymph combines with hepatic lymph to overload the thoracic duct.
On the other hand, in schistosomal hepatic fibrosis with presinusoidal block, the extrahepatic
portal bed is probably the sole source of excess thoracic duct lymph.
The observation by Dumont et al. (4) that in patients with hepatic cirrhosis or congestive'heart
failure the splenic pedicle contains a number of dilated lymphatics, is similar
to that previously described by Baggenstoss and Cain (1) and Baggenstoss (2), at
the hilus of the liver. This finding suggests that part of the excess extrahepatic lymph
originates from the spleen. To evaluate this possibility, the present study was undertaken
to determine the role played by the spleen in excess lymph production in patients
with schistosomal hepatic fibrosis, a disorder characterized by presinusoidal portal block.