I. Preface
Cerebral Venous and Sinus Thrombosis CVT is a rare form of ischemic venous stroke, accounting for 0.5% of all strokes, first reported by Ribes in 1825. It consists of three types: (1) cortical vein thrombosis: rarely solitary, but mostly associated with DST. (2) dural sinus thrombosis (DST). (3) Deep cerebral venous thrombosis (DCVT). DCVT is mostly seen in pregnant women, women taking oral contraceptives and young people under 45 years old, and the most risky period is late pregnancy and the first 4 weeks after delivery. 73% of women with DCVT occur just after delivery, and the prognosis is not as poor as previously thought, and most of them have a good prognosis with a mortality rate of less than 10% (previously reported mortality rate of 30%-50%). Wang Aihua, Department of Neurology, Qifoshan Hospital, Shandong Province, China
Second, the anatomical characteristics of cerebral veins
1. veins have no muscle fibers, no contractility, no valves, and do not travel with arteries. 2. cerebral veins have abundant anastomotic branches. The superficial and deep veins are injected into the dural sinus first, and the superior sagittal sinus also drains the blood from the platysmal vein. 3. The venous pressure is close to the intracranial pressure.
Etiology
1. congenital factors: prothrombin deficiency, protein S and protein C deficiency, Leiden V factor mutation, thromboxane gene mutation, etc. 2. infectious factors: otitis, mastoiditis, sinusitis, meningitis, brain abscess, and systemic infections, etc. 3. immune diseases: SLE, Wegener’s granulomatosis, sarcoidosis and Behcet’s disease, ulcerative ulcerative disease, and sarcoidosis. ‘s disease, ulcerative colitis and clonorchiasis, etc. 4. Acquired thrombosis-prone states: including nephrotic syndrome, antiphospholipid antibody syndrome, hyperhomocysteinemia, pregnancy and puerperium. 5. Hematologic disorders: erythrocytosis, leukemia, anemia, paroxysmal nocturnal hemoglobinuria and congenital or acquired disorders of coagulation mechanisms, etc. 6. Medications: oral contraceptives, winter aminase, postmenopausal hormone replacement therapy and steroid therapy, etc. 7 . Trauma and mechanical manipulation: head trauma, neck trauma involving the jugular vein, neurosurgery, lumbar puncture, jugular catheterization, etc. 8. Other: dural arteriovenous malformations, cerebral arteriovenous malformations, severe dehydration, wasting diseases (cachexia, advanced cancer), heart failure, shock, ketoacidosis, hyperthermia, intracranial tumors and other malignancies can cause or contribute to CVST. 9. About 15% of The cause of CVT is unknown (20-25%).
IV. CVT clinical symptoms
The clinical manifestations of CVST vary greatly and are not specific, and can have multiple forms of pathogenesis and a variety of clinical manifestations, and can even “mimic” the clinical manifestations of many diseases. The clinical manifestations depend on the site and extent of thrombosis, the rate of progression, the venous collateral circulation, the extent and degree of secondary brain parenchymal damage, and the presence of infection. The most common signs and symptoms are, in order of importance, headache (80-90%), seizures (40%), focal neurological deficits, impaired consciousness, and optic nerve papilledema. CVT should be considered in cases of headache and optic papilloedema or diplopia, even if there are no other focal signs suggesting only idiopathic intracranial hypertension. rare or rare are cavernous sinus syndrome, subarachnoid hemorrhage, migraine attacks with aura, restrictive headache, transient ischemic attack, tinnitus, simple psychiatric symptoms, and single or multiple cranial nerve damage.
V. Imaging diagnosis
(a) CT: CT is the preferred method for neurological emergencies, although about 25-30% of CVT have normal CT performance, it can be used to exclude other lesions. 1. Direct CT signs: (1) Strip sign: refers to an empty triangular shadow visible in the posterior corner of the superior sagittal sinus after enhancement, with a positive rate of 70%. CT flat scan of the superior sagittal sinus shows high density. (2) triangular sign (empty delta sign): the striated sign refers to the embolized vein seen before enhancement, and the CT scan shows high density in the cortical vein, straight sinus and Galen’s vein, etc. 2. Indirect CT signs: hemorrhage or hemorrhagic infarction, basal ganglia and bilateral thalamic infarction, ventricular shrinkage (increased intracranial pressure, cerebral edema), etc.
(2) MRI: The thrombus signal on MRI varies with time: 1-5 d after onset, normal vascular flow-void phenomenon disappears, T1 isosignal, T2 low signal; 6-15 d after onset, T1 and T2 are high signal; 16 d-3 months, T1 and T2 signals weaken, flow-void signal gradually increases; persistent occlusion is manifested as 4 months after onset, some patients still see persistent intra-luminal isosignal, no normal flow-void signal. In some patients, a persistent intraluminal iso-signal is seen 4 months after the onset of occlusion. The use of MR alone is limited because in the ultra-early stages of acute thrombosis, the influence of flow artifacts can lead to false-positive results that do not show high-signal changes on T1- and T2-weighted images. In the 3-5 days after the onset, thrombus in the vein is isosignal on T1 and hyposignal on T2, and is sometimes not easily distinguished from normal veins.
(iii) MRV: MRV can show cerebral venous sinuses and veins well, but using MRV alone cannot distinguish between venous thrombosis or cerebral venous dysplasia, especially one side of the transverse sinus and sigmoid sinus dysplasia is common. Therefore, the combination of cerebral MRI, which detects thrombus in a venous sinus or vein, and cerebral MRV, which detects occlusion or stenosis in the same venous sinus or vein, is considered to be the gold standard for the diagnosis of CVST.
(iv) DSA: DSA is used in patients who are unable to undergo MRI and MRV or in whom the diagnosis is unclear, especially in patients with isolated cortical vein thrombosis. Best sign – partial/complete filling defect of vein or venous sinus Advantages: dynamic observation of changes in intravascular thrombosis, providing an objective basis for clinical treatment, especially interventional treatment. Typical signs: 1. partial or complete cerebral venous/sinus filling defect. 2. poor or abrupt truncation of cortical veins in the venous phase, or a small avascular area surrounded by dilated spiral collateral branches, suggesting cortical vein thrombosis. 3. delayed emptying: DSA shows a significant prolongation of the cerebral arteriovenous circulation time (from the time of visualization of the intracranial segment of the internal carotid artery to the disappearance of the venous collateral sinus) to 11 seconds or more. The longest was more than 20 seconds.
(v) D-dimer: The D-dimer level in patients with CVT varies widely and is not specific. A recent study of 26 patients with CVST showed that 20 of them had elevated D-dimer within 22 days of onset (27), so patients with suspected elevated D-dimer should undergo urgent MR and MRV examinations to determine whether they have CVT. Therefore, patients with suspected elevated D-dimer should undergo urgent MR and MRV examinations to determine whether they have CVT.
VI. Treatment and prognosis
Treatment includes anti-infection, discontinuation of oral contraceptives, anticoagulation (heparin, warfarin), thrombolysis (urokinase, t-PA), reduction of cerebral edema, antiepilepsy, etc., in response to causative factors. Treatment principles: Initiate effective anticoagulant doses of UFH or LMWH, regardless of the presence of ICH, followed by the application of vitamin K antagonist therapy
(i) Anticoagulation: the optimal course of oral anticoagulants after the acute phase is not known; venous sinus thrombosis is a very serious venous thrombosis, so the criteria for long-term treatment should be appropriately relaxed. If CVT is secondary to risk factors that can rapidly subside, oral anticoagulation therapy can be continued for up to 3 months. For primary CVT, combined extracranial venous thrombosis, and patients with a mild genetic predisposition to thrombosis, such as protein C and protein S deficiency, heterozygous V factor Leiden mutation, or prothrombin G20210A mutation, oral anticoagulation therapy is recommended for 6 to 12 months. In patients with a severe genetic predisposition to thrombosis, such as antithrombin deficiency, pure heterozygous factor V Leiden mutation, or ≥2 thrombotic tendencies, the risk of recurrence is high and long-term anticoagulation therapy should be considered. Permanent anticoagulation is also recommended for patients with ≥2 objective evidence of primary extracranial venous thrombosis.
(ii) Fibrinolytic therapy: Studies have shown that 9-13% of patients with CVT treated with anticoagulation throw a poor outcome, and anticoagulation alone may not lyse large, extensive thrombi, with partial or complete recanalization rates of 47-100% for CVT treated with anticoagulation alone. Overall, the application of thrombolytic therapy may be effective if clinical deterioration continues despite anticoagulation or if intracranial pressure continues to rise. Most samples were of small sample sizes.
(iii) Aspirin: There are no controlled trials or observational studies directly evaluating the role of aspirin in the treatment of CVT.
(iv) Steroid hormones: Steroid hormones may help to reduce vasogenic edema, but hormones can also increase hypercoagulability. Guideline recommendation: even if CT/MRI suggests brain parenchymal damage, steroids cannot be recommended unless there is other underlying disease requiring steroids.
(E) Thrombolysis and interventional therapy: Local thrombolysis of CVT by microcatheter rtPA or urokinase has only been studied in a few small samples so far, and there is no unified standard for its administration method. Interventional treatment including balloon dilation, stent implantation, intravenous sinus tube thrombolysis, carotid artery thrombolysis, etc. have been successfully reported in individual cases or small samples at home and abroad.
(vi) Symptomatic and etiological treatment: antiepileptic treatment, treatment of lowering intracranial pressure, application of broad-spectrum antibiotics for infectious cases, surgical treatment, treatment of systemic diseases, etc. When hypercoagulable state is found, long-term anticoagulation therapy should be considered, and if the patient has a congenital propensity for thrombosis, family epidemiological investigation should be performed as a genetic risk factor and prophylactic treatment should be given.