A case of portal vein thrombosis caused by blunt abdominal trauma in a patient with low protein C activity.

Portal vein thrombosis (PVT) is caused by several conditions including infection, malignancies, surgery, medications, and coagulation disorders. However, PVT caused by low-energy injury is very rare. A 51-year-old man visited a clinic with a 2-day history of abdominal pain following blunt abdominal trauma. Contrast-enhanced computed tomography (CT) revealed thrombosis in both the portal vein and splenic vein, and he was transferred to our hospital with a diagnosis of PVT. Anticoagulant therapy was initiated using unfractionated heparin. A repeat CT scan revealed enlargement of the thrombus, which occluded the main trunk and first right branch of the portal vein. Laboratory data before heparin administration suggested low protein C activity. Anticoagulation therapy was continued with intermittent assessment of the size of the thrombus and degree of coagulation. On day 23, enhanced CT showed marked shrinkage of the thrombus compared with that on day 8. On day 30, the patient was discharged with a therapeutic prothrombin time-international normalized ratio. Here we present a case of PVT caused by low-energy trauma of the upper abdomen in a patient with a background of low protein C activity that was successfully treated without invasive surgery.