Cerebral Venous Thrombosis

Thrombosis of the venous channels in the brain is an uncommon cause of cerebral infarction relative to arterial disease, but it is an important consideration because of its potential morbidity.

Knowledge of the anatomy of the venous system is essential in evaluating patients with cerebral venous thrombosis (CVT) since symptoms associated with the condition are related to the area of thrombosis. For example, cerebral infarction may occur with cortical vein or sagittal sinus thrombosis secondary to tissue congestion with obstruction.

Lateral sinus thrombosis may be associated with headache and a pseudotumor cerebri–like the picture. Extension into the jugular bulb may cause jugular foramen syndrome, while cranial nerve palsies may be seen in cavernous sinus thrombosis as a compressive phenomenon. Cerebral hemorrhage also may be a presenting feature in patients with venous sinus thrombosis.

The following guidelines for CVT have been provided by the American Heart Association and the American Stroke Association :

• In patients with suspected CVT, routine blood studies consisting of a complete blood count, chemistry panel, prothrombin time, and activated partial thromboplastin time should be performed.
• Screening for potential prothrombotic conditions that may predispose a person to CVT (eg, use of contraceptives, underlying inflammatory disease, infectious process) is recommended in the initial clinical assessment.
• Testing for prothrombotic conditions (including protein C, protein S, or antithrombin deficiency), antiphospholipid syndrome, prothrombin G20210A mutation, and factor V Leiden can be beneficial for the management of patients with CVT. Testing for protein C, protein S, and antithrombin deficiency is generally indicated 2-4 weeks after completion of anticoagulation. There is a very limited value of testing in the acute setting or in patients taking warfarin.
• In patients with provoked CVT (associated with a transient risk factor), vitamin K antagonists may be continued for 3-6 months, with a target international normalized ratio of 2.0-3.0.
• In patients with unprovoked CVT, vitamin K antagonists may be continued for 6-12 months, with a target international normalized ratio of 2.0-3.0.
• For patients with recurrent CVT, venous thromboembolism (VTE) after CVT, or first CVT with severe thrombophilia (ie, homozygous prothrombin G20210A; homozygous factor V Leiden; deficiencies of protein C, protein S, or antithrombin; combined thrombophilia defects; or antiphospholipid syndrome), indefinite anticoagulation may be considered, with a target international normalized ratio of 2.0-3.0.
• For women with CVT during pregnancy, low-molecular-weight heparin (LMWH) in full anticoagulant doses should be continued throughout pregnancy, and LMWH or vitamin K antagonist with a target international normalized ratio of 2.0-3.0 should be continued for ≥6 weeks postpartum (for a total minimum duration of therapy of 6 months).
• It is reasonable to advise women with a history of CVT that future pregnancy is not contraindicated. Further investigations regarding the underlying cause and formal consultation with a hematologist or maternal-fetal medicine specialist are reasonable.
• It is reasonable to treat acute CVT during pregnancy with full-dose LMWH rather than unfractionated heparin.
• For women with a history of CVT, prophylaxis with LMWH during future pregnancies and the postpartum period is reasonable.