Acute Portal Vein Thrombosis Secondary to COVID-19 Vaccination.

Portal vein thrombosis (PVT) is a partial or complete occlusion of the hepatic portal vein most frequently seen in patients with cirrhotic liver disease. Various non-cirrhotic conditions including inherited prothrombic blood disorders, neoplasms, and inflammatory diseases create hypercoagulable states that predispose individuals to blood clotting. Rarely does an exhaustive workup leave the etiology of a PVT unknown or unclear, and even more uncommon is a potential new etiology suspected. Our patient is a 34-year-old female, with no significant risk factors for pathologic clotting, who was diagnosed with an acute PVT several days after receiving the Moderna coronavirus disease 2019 (COVID-19) vaccine.