This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Medicine
Sudden abdominal pain in polycythemia vera is due to 
Select and explain. 
A. Hepatic vein thrombosis, B. Hyperviscosity, C. Pancreatitis, D. Small bowel-obstruction
A: Hepatic vein thrombosis
Answer: A: Hepatic vein thrombosis 
Explanation: (A) (Hepatic vein thrombosis) (898-H 18th)* Intra abdominal venous thrombosis is particularly common in young women and may be catastrophic if a sudden and complete obstruction of the hepatic vein occurs (898- H 18th)* Thrombosis sometimes also occurs in the hepatic veins (producing Budd- chiary syndrome) and the porlal and mesenteric veins (leading to bowel infarction) (619- Robbins south- asian edition)* Intense pruritis and peptic ulceration may occurs both possibly resulting from the release of histamine from basophils (619- Robbins)Hepatic vein thrombosis is associated with (indecreasing order of frequency)* Polycythemia vera* Pregnancy* Post partum state* Use of oral contraceptions* Paroxysmal nocturnal hemoglobinuria (PNH)* Hepatocellular carcinomaBudd chiary's syndrome - characerised by* Hepatomegaly* Weight gain* Ascites* Abdominal vein