Cerebral Venous Sinus Thrombosis

Cerebral venous sinus thrombosis (CVT) is a clot in a dural venous sinus and/or cortical or deep cerebral vein. Unlike an arterial ischemic stroke, in which blood cannot enter a downstream arterial territory, CVT obstructs blood leaving the brain. The resulting back-pressure matters. Venous congestion raises intracranial pressure and causes cerebral edema. As pressure rises within the affected veins, tissue may infarct; because congested veins can rupture, the infarct may be hemorrhagic. A scan showing intracerebral hemorrhage therefore does not exclude CVT. In the right clinical setting, it may be part of the disease process. CVT often develops over hours to days rather than producing the abrupt, fixed deficit typical of an arterial large-vessel occlusion. Headache may be the dominant feature, sometimes before any focal finding emerges. That pattern is why CVT is easily mistaken for migraine, postpartum headache, seizure disorder, or an uncomplicated arterial stroke.