Very common risk factor for both venous and arterial disease. High homocystine levels are synergist risk factor with factor V Leiden. Acquired Pregnancy - DVT and its sequelae pulmonary embolism is the most common cause of maternal death. Increased levels of factor VII, VIII and fibrinogen are also seen. Inflammatory disorders -Inflammatory bowel disease, infections, etc.
Thrombosis can predate the appearance of the myeloproliferative syndrome by months to years.
The key to diagnosing the exact cause of an hypercoagulable state is to try to determine if it is an acquired or inherited disorder. The key is a good family history. Most patient with an inherited disorder will have several relatives afflicted with thrombosis. A good thrombotic family history is mandatory on any patient with thrombosis. Studies on families with protein C and protein S deficiency show that deficient individuals can have their first thrombosis as late as age 70.