patient education : 04088--What is Cerebral Venous Sinus Thrombosis
Handout File:
PE04088_eng_CVST September 2023.pdf
—
PDF document,
645 KB (661366 bytes)
-
document content:
WHAT IS CEREBRAL VENOUS SINUS THROMBOSIS?
Cerebral venous sinus thrombosis (CVST) is the presence of a blood clot in the large veins of the brain called the cerebral venous sinuses, which drain blood from the brain. CVST is an uncommon and frequently unrecognized type of stroke that affects about 5 people per million per year and accounts for less than 1% of all strokes. CVST is more commonly seen in young individuals.
WHAT AND WHERE ARE THE DURAL VENOUS SINUSES?
Like every organ of our body, the brain has a system of veins by which blood returns to the lungs to get more oxygen. This system of veins begins as a collection of small channels that receive blood from areas throughout the brain. As these veins extend away from the brain’s tissues, they become fused with one another to form larger veins that gather between the brain and the skull bone to form what is called the cerebral venous sinuses.
HOW CAN A CVST CAUSE DAMAGE TO THE BRAIN?
Eighty-five percent of people who are diagnosed with cerebral venous sinus thrombosis have a tendency to form blood clots. Some of the conditions or events that make people more likely to form blood clots include: head injury, the last three months of pregnancy or three months following delivery, childbirth, use of birth control pills, and infections (especially in the face, eyes, or ears).
When a blood clots forms inside of one of the brain's sinuses, it causes a backup of blood preventing blood from leaving the brain's tissues. At first, this is not a problem, as the small veins have some room to enlarge in order to accommodate for the extra blood. However, as time goes on and new oxygen-rich blood continues to enter the brain's tissues through the arteries, the extra blood begins to create pressure on the walls of the veins until they burst. The bursting of the vein causes bleeding into the brain, which can damage the surrounding brain tissue and cause stroke-like symptoms.
WHAT ARE THE SYMPTOMS OF CEREBRAL VENOUS SINUS THROMBOSIS?
One of the known features of a CVST is that it can cause a wide range of symptoms from a mere headache to sudden and complete paralysis of one side of the body. More than 90% of people diagnosed with cerebral venous sinus thrombosis complain of severe headaches, while 50% of them have stroke-like symptoms. These symptoms can include weakness, numbness or tingling, difficulty speaking, vision changes, room spinning, and difficulty walking. Approximately 40% of people with CVST will have seizures.
HOW IS CVST DIAGNOSED?
The diagnosis is usually made by using computed tomography (CT) scan with contrast or magnetic resonance imaging (MRI) with MR venogram to demonstrate blockage of the venous sinuses by a blood clot. An eye exam may be performed to see if there appears to be increased pressure on the brain. Blood tests looking for a reason for blood clot formation are also performed.
HOW IS CEREBRAL VENOUS SINUS THROMBOSIS TREATED?
When cerebral venous sinus thrombosis causes a large amount of bleeding inside the brain, surgery is required in order to decrease the pressure build up in the skull. This is important as bleeding in the brain can lead to rapid brain compression and death. The procedure performed is called a decompressive hemicraniectomy where a part of the skull bone may be removed to allow for the brain to swell outwards rather than inwards.
Unless it is medically contraindicated, every person who is diagnosed with CVST should receive blood thinners, such as heparin, Coumadin, and Lovenox. These medications are given in order to prevent the enlargement of the blood clot that sits inside the affected sinus waiting to be absorbed, and to prevent the formation of new and possibly more serious blood clots.
