Once blood has perfused the brain and enriched its cells with oxygen and nutrients, it is drained by cerebral veins. These veins drain into dural venous sinuses which, in turn, drain into the jugular veins in the neck that carry blood back to the heart. A dural sinus thrombosis is the occlusion of a dural sinus by a blood clot (or thrombus). Because of this occlusion, blood flowing out of the brain is backed up, and the brain tissue becomes congested. As a result, both ischemia and hemorrhage may occur.
What are the symptoms of dural sinus thrombosis?
A dural sinus thrombosis may present as a stroke (hemorrhagic infarct), headache, or seizure. When many dural sinuses are occluded, a life-threatening increase in intracranial pressure can result.
What causes thrombosis of a dural sinus?
In 10% of cases dural sinus thrombosis is caused by an infection in the ear or nasal sinuses. More often, the cause is related to hypercoagulability of the blood, which may occur with pregnancy, birth control pills, or circulating antibodies.
How is a dural sinus thrombosis treated in a neuro-ICU?
The mainstay of treatment for dural sinus thrombosis is anticoagulation with blood thinners (heparin and coumadin). This treatment was once controversial because the use of anticoagulants to promote blood flow was thought to exacerbate the cerebral hemorrhaging associated with the disease. However, research has shown that anticoagulation is an effective treatment for dural sinus thrombosis, because it prevents extension of the thrombus to uninvolved areas, and promotes lysis (dissolving) of existing thrombus. Seizures are a common complication and can be prevented with anticonvulsants. Increased intracranial pressure, which can be life threatening, can be managed with an intracranial pressure monitor.
What can be done if the above measures do not work?
In the most severe cases, clot-busting drugs (thrombolytics) can be delivered via a small catheter directly into the thrombus to dissolve them. Recent studies have shown that infusions of urokinase are effective at managing severe dural sinus thrombosis. This type of treatment is experimental, and probably is most effective when given immediately after a sudden major deterioration occurs. Continuous monitoring of neurologic status in a neuro-ICU can make this possible.