Occlusion of the splenic vein, without occlusion of the portal vein, can lead to a localized, regional splenic hypertension, referred as sinistral or left-sided portal hypertension in the human radiology literature. In people, may cause gastrointestinal hemorrhages from the esophageal and gastric varices and the primary pathology usually includes pancreatitis and pancreatic neoplasms. The final diagnosis of localized splenic hypertension necessitates accompanying normal liver functions and a patent extrahepatic portal vein. Following obstruction, the resultant elevated splenic bed venous pressure causes formation of collateral routes, the extent of which depends upon the level and degree of obstruction. In this retrospective descriptive study, authors assessed the collateral pathways in dogs with isolated splenic vein occlusion and possible regional splenic vein hypertension. Out of the 46 patients initially recruited, 25 were excluded due to the presence of concomitant portal thrombosis and direct/indirect CT signs of portal hypertension. The remaining 21 dogs had clinicopathological tests suggesting normal liver function. The causes of obstruction identified included splenic pedicle torsion, tumoral splenic vein invasion, and splenic vein thrombosis. Four of 21 dogs with isolated splenic vein obstruction showed collateral pathways through the left gastroepiploic vein (4/4), left gastric vein (2/4), and splenogonadal vein (1/4). The diagnosis of isolated, regional splenic hypertension should be based on clinical, biochemical, and radiological evaluation. Computed tomography is an excellent tool to assess the collateral patterns and to determine the underlying cause.
© 2020 American College of Veterinary Radiology.