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CVST is a type of brain stroke caused by blood clots in a vein. This rare blood clot disorder prompted the current pause of Johnson & Johnson (J&J) COVID-19 vaccine, as well as Astrazeneca vaccine.
Pathophysiology, signs and symptoms, risk factors, diagnosis, treatment and prognosis.
Other names: Cerebral vein thrombosis, Cerebral sinovenous thrombosis, Cerebral venous thrombosis (CVT), Cerebral venous and sinus thrombosis, Cerebral venous sinus thrombosis (CVST), Cerebral sinovenous thrombosis (CSVT), Cerebral vein and dural sinus thrombosis, Sinus and cerebral vein thrombosis.
Cerebral venous sinus thrombosis, CVST, occurs when a blood clot forms and blocks a vein in the brain. Blood is transported to the brain in arteries. After delivering oxygen and nutrients, it leaves in veins. Small veins of the brain are called cerebral veins. They drain into large veins, called sinus veins, or venous sinuses. Sinus veins empty into jugular veins, which carry the blood back to the heart. A blockage in a vein causes the blood to back up in the brain, increasing pressure, causing headache, which is often severe. The increased pressure may damage the surrounding brain tissue, producing stroke symptoms such as blurred vision, confusion, loss of consciousness, loss of movement control, seizure or coma. The engorged blood vessel may also rupture, bleeding into the brain, a condition known as “venous hemorrhagic stroke”. Unlike arterial thrombosis that causes the typical brain stroke, venous thrombosis usually develops slowly. This is due to the slow growth of blood clots in veins, and the ability of the venous system to form new vessels to bypass an obstruction, maintaining more or less normal flow at first. In most cases, symptoms develop gradually, over days, weeks or even months, but sudden onset may also occur. CVST is a rare type of stroke that can affect all age groups, including infants. Risks factors include: having inherited blood disorders, systemic conditions, cancers; use of certain medications, and some infections. Women of reproductive age are more at risk due to pregnancy and use of birth control pills. Infants with difficult birth, or whose mothers had certain infections, are also more vulnerable. CVST is often misdiagnosed due to its rarity, wide spectrum of symptoms, and the fact that symptoms can appear suddenly or gradually. The standard MRI or CT scans used to detect stroke are often normal in CVST. To diagnose CVST, the veins must be specifically examined in a procedure called magnetic resonance venography. CVST must be suspected in patients of any age who have severe headache that doesn’t go away, and any risk factors for clotting disorders. Timely diagnosis and prompt treatments are essential for survival. Immediate treatment includes blood thinners, typically intravenous heparin, or subcutaneous low-molecular-weight heparin. The goal is to prevent the enlargement of existing clots and formation of new clots, while letting the body’s own system dissolves the existing clots slowly, typically over weeks or months. However, patients who have bleeding must be monitored closely to ensure it does not worsen. If the patient deteriorates despite heparin, catheter-directed procedures to breakdown blood clots may be considered. Once the patient is out of danger, an oral anticoagulant such as warfarin is typically given for 3 to 6 months, although patients with known clotting disorders may need to take warfarin for life. About 3 in 4 patients fully recover, but it may take some time to get back to normal.
