Walsh & Hoyt: Causes

A wide variety of conditions can cause CVT. These can be divided into congenital and acquired thrombophilias, abnormalities of blood flow, and disorders involving the vessel wall. In the pre-antibiotic era, septic CVT was relatively common, but in recent years prothrombotic states are more frequently identified. A number of congenital thrombophilias have been associated with an increased risk of CVT. The most commonly identified have been the factor V Leiden mutation and the G20210A-prothrombin gene mutation. Other studies have found associations with antiphospholipid antibodies, hyperhomocysteinemia, antithrombin III deficiency, protein S or C deficiency, and sickle cell disease. Occasional patients harbor more than one such mutation and in some patients a combination of congenital and acquired factors may cause thrombosis. The clinical corollary of this observation is that a full coagulation work-up should be undertaken in all patients with CVT even when an apparent inciting event, such as pregnancy, oral contraceptives, or recent surgery, has been identified.