There are many causes of portal vein thrombosis including hypercoagulable states (such as anti-phospholipid antibody syndrome, protein S deficiency, protein C deficiency, and antithrombin II deficiency), myeloproliferative diseases, birth control pill usage, polycythemia vera, and sickle cell anemia. Inflammatory causes include inflammatory bowel disease, Behcet’s disease, and pancreatitis. Infectious diseases such as appendicitis and diverticulitis can rarely cause portal vein thrombosis. Medical or surgical interventions to treat neoplasms of the liver also have been shown to cause portal vein thrombosis such as chemo-embolization, alcohol injection, and partial hepatectomy. Portal vein thrombosis also occurs in patients undergoing liver transplant, sclerotherapy, and transjugular intrahepatic portosystemic shunting (TIPS) placement. Miscellaneous causes include cirrhosis, hepatocellular carcinoma, and trauma.
