Cerebral venous sinus thrombosis (CVST), cerebral venous and sinus thrombosis or cerebral venous thrombosis (CVT), is the presence of a blood clot in the dural venous sinuses (which drain blood from the brain), the cerebral veins, or both. Symptoms may include severe headache, visual symptoms, any of the symptoms of stroke such as weakness of the face and limbs on one side of the body, and seizures, which occur in around 40% of patients.The diagnosis is usually by computed tomography (CT scan) or magnetic resonance imaging (MRI) to demonstrate obstruction of the venous sinuses. After confirmation of the diagnosis, investigations may be performed to determine the underlying cause, especially if one is not readily apparent. Treatment is typically with anticoagulants (medications that suppress blood clotting) such as low molecular weight heparin. Rarely, thrombolysis (enzymatic destruction of the blood clot) or mechanical thrombectomy is used, although evidence for this therapy is limited. The disease may be complicated by raised intracranial pressure, which may warrant surgical intervention such as the placement of a shunt. Signs and symptoms
Nine in ten people with cerebral venous thrombosis have a headache; this tends to worsen over the period of several days, but may also develop suddenly (thunderclap headache). The headache may be the only symptom. Many have symptoms of stroke: inability to move one or more limbs, weakness on one side of the face or difficulty speaking.
The condition does not typically lead to hydrocephalus, however, because there is no difference in pressure between various parts of the brain. However, those who have deep cerebral venous sinus thrombosis or oedema at basal ganglia are more prone to hydrocephalus development.Any blood clot forms due to an imbalance between coagulation (the formation of the insoluble blood protein fibrin) and fibrinolysis. The three major mechanisms for such an imbalance are enumerated in Virchows triad: alterations in normal blood flow, injury to the blood vessel wall, and alterations in the constitution of blood (hypercoagulability). Most cases of cerebral venous sinus thrombosis are due to hypercoagulability. The inflammatory response and prolonged immobilization of patients with COVID-19 may also help explain the formation of CVST.It is possible for the clot to break off and migrate (embolise) to the lungs, causing a pulmonary embolism. An analysis of earlier case reports concludes that this occurs in about 10% of cases, but has a very poor prognosis.Central venous thromboses usually involve the dural sinuses with or without involvement of the cortical veins; isolated cortical venous thromboses are extremely rare with only about 100 cases reported. Treatment
Various studies have investigated the use of anticoagulation to suppress blood clot formation in cerebral venous sinus thrombosis. Before these trials had been conducted, there had been a concern that small areas of hemorrhage in the brain would bleed further as a result of treatment; the studies showed that this concern was unfounded.