This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cirrhosis, Subject name: Pathology
A 34 year old female with history of oral contraceptive pills (OCP) usage, was brought to the ER with hematemesis and severe acute RUQ abdominal pain. She have a history of DVT. Physical evaluation reveals ascites and tender heatomegaly. Which of the following is the most likely cause for this? 
Select and explain. 
A. Obstruction of the common bile duct, B. Obstruction of the intrahepatic sinusoids, C. Thrombosis of the hepatic aery, D. Thrombosis of the hepatic veins
D: Thrombosis of the hepatic veins
Answer: D: Thrombosis of the hepatic veins 
Explanation: The above given clinical scenario is suggestive of Budd-Chiari syndrome. Caused by obstruction of two or more major hepatic veins (hepatic vein thrombosis). Obstruction of a single main hepatic vein is clinically asymptomatic. Heaptic damage occurs due to increased intrahepatic blood pressure. Hepatic vein thrombosis is associated with myeloproliferative neoplasms such as polycythemia vera, thrombophilic states (OCP use, inherited thrombophilias, etc. ), antiphospholipid antibody (APLA) syndrome, paroxysmal nocturnal hemoglobinuria (PNH), and intraabdominal cancers, paicularly hepatocellular carcinoma. Clinically, Budd-Chiari syndrome is characterized by severe right upper quadrant abdominal pain, ascites, tender hepatomegaly, and hematemesis (variceal bleed). Microscopically, the affected hepatic parenchyma reveals severe centrilobular congestion and necrosis.