What is Cerebral Venous Sinus Thrombosis?
Cerebral venous sinus thrombosis is a type of cerebrovascular disease wherein there is an obstruction of one of the venous sinuses by a clot of blood, resulting in the infarction or death of brain cells. This infarction is more commonly known as stroke. Although the symptoms are dependent on the site of sinus thrombosis, symptoms commonly reported include headache, blindness, and weakness. Diagnosis is confirmed through imaging modalities, such as a computed tomography (CT) scan and magnetic resonance imaging (MRI). Treating cerebral venous sinus thrombosis involves medical stabilization and thrombolytic therapy.
There are two major types of thrombosis based on the kind of blood vessel affected. An arterial thrombosis involves an artery, and a venous thrombosis involves veins and dural sinuses or spaces. In arterial thromboembolic strokes, a blood clot from the heart is thrown into the arterial circulation, reaches the middle cerebral artery (MCA), and causes a stroke. This is in contrast to cerebral venous sinus thrombosis, wherein a blood clot forms in the sinus spaces.
Although cerebral venous sinus thrombosis is significantly less common than arterial thrombosis, it is an important consideration because it causes disability. Different causes of this disease have been identified. Venous thrombosis of the lateral or sagittal sinus may occur as a complication of prolonged usage of oral contraceptives and pregnancy. Another cause is the infection of the paranasal and frontal sinuses, usually from Staphylococcus. Trauma, whether due to accidents or neurosurgical procedures, may also cause cerebral venous sinus thrombosis.
Other factors that increase the risk of cerebral venous sinus thrombosis include inflammatory bowl disease and corticosteroid use, deficiencies of anticoagulation proteins, and blood diseases. People who have systemic lupus erythematosus or nephrotic syndrome are also at increased risk. Other factors include dehydration and living in high altitudes. All of these risk factors generally produce a hypercoagulable state and make the blood more prone to clot formation.
The primary mode of diagnosing cerebral venous sinus thrombosis is by imaging. A CT scan is often the first imaging modality requested, but it provides limited information and is usually normal unless hemorrhage is present. Nevertheless, it is important for eliminating the suspicion for other conditions. Magnetic resonance venography (MRV) gives a better view of the pattern of infarction and may show the absence of normal blood flow in the cerebral venous channels. MRV is generally the imaging of choice for the dural venous sinuses and cerebral veins.
Treatment of cerebral venous sinus thrombosis involves medical and surgical management. At the emergency room, the patient’s head is elevated at an angle of about 30 to 40 degrees to decrease intracranial pressure. If seizure is present, an anticonvulsant, such as fosphenytoin, sodium valproate, or phenobarbital is injected. Anticoagulant or thrombolytic therapy is then initiated to restore venous blood flow and decrease intracranial pressure.
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