What are the differences between cerebral venous thrombosis (CVT) and stroke?

Key Differences Between Cerebral Venous Thrombosis (CVT) and Stroke

Cerebral venous thrombosis (CVT) differs from arterial stroke primarily in its clinical presentation, pathophysiology, affected population, and treatment approach, with CVT typically presenting with more gradual symptom onset and affecting younger patients.

Pathophysiology

• CVT occurs due to thrombosis in the cerebral veins or dural sinuses, causing impaired venous drainage and increased intracranial pressure, while arterial stroke results from occlusion or rupture of cerebral arteries 1
• CVT represents only 0.5-1% of all strokes, making it a relatively uncommon form of cerebrovascular disease 1

Clinical Presentation

• Headache is the most prominent symptom in CVT (present in nearly 90% of patients), typically diffuse and progressively worsening over days to weeks, whereas headache is less common in arterial stroke 1
• CVT has a more subacute presentation with slower symptom progression - only 37% present acutely (<48 hours), 56% subacutely (48 hours to 30 days), and 7% chronically (>30 days) 1
• Seizures occur in approximately 40% of CVT patients, which is significantly higher than in arterial stroke 1
• Bilateral brain involvement is more common in CVT, particularly with deep venous system thrombosis, which can cause bilateral thalamic involvement and altered consciousness without focal signs 1

Patient Demographics

• CVT predominantly affects younger individuals, with 78% of cases occurring in patients under 50 years of age 1, 2
• Women are more frequently affected than men, particularly those taking oral contraceptives or who are pregnant/postpartum 2, 3

Risk Factors

• CVT is strongly associated with prothrombotic conditions including inherited thrombophilias (protein C deficiency, protein S deficiency, antithrombin III deficiency, factor V Leiden) 1, 2
• Other significant risk factors include oral contraceptive use, pregnancy, puerperium, malignancy, and inflammatory conditions 1, 2

Diagnostic Approach

• Non-contrast CT has limited sensitivity for CVT (abnormal in only 30% of cases), whereas it more readily detects arterial stroke 1
• MRI with MR venography is the preferred diagnostic modality for CVT, showing both venous occlusion and parenchymal changes 1, 2
• D-dimer can be helpful in excluding CVT when negative, though it has poor specificity 1

Imaging Findings

• CVT may show hemorrhagic infarction that crosses arterial boundaries, which is uncommon in arterial stroke 1
• The "empty delta" sign on contrast-enhanced CT (filling defect within the superior sagittal sinus) is characteristic of CVT 1
• Venous infarcts are often hemorrhagic and located near venous sinuses, unlike arterial strokes which follow arterial territories 1

Treatment

• Anticoagulation is the mainstay of treatment for CVT, even in the presence of hemorrhagic lesions, which contrasts with arterial stroke where anticoagulation may be contraindicated with hemorrhage 4, 5
• Endovascular interventions may be considered in CVT patients who deteriorate despite anticoagulation 4, 5

Prognosis

• CVT generally has a more favorable prognosis than arterial stroke when diagnosed and treated early 6, 7
• The mortality rate in CVT is lower than in arterial stroke, with most patients making a full recovery 8, 7

Common Pitfalls

• Delayed diagnosis is common in CVT (median 7 days from symptom onset to diagnosis) due to its variable presentation and slower progression 1
• CVT may be misdiagnosed as idiopathic intracranial hypertension, especially when presenting with isolated headache and papilledema 1
• Normal non-contrast CT does not exclude CVT; further imaging with CTV or MRV should be pursued when clinical suspicion is high 1, 3