From the Guidelines
Cerebral venous sinus thrombosis (CVST) is caused by multiple factors including prothrombotic conditions, infections, medications, and mechanical factors, and a comprehensive workup including complete blood count, coagulation profile, thrombophilia panel, and imaging studies such as MRI with venography or CT venography is necessary to determine the underlying cause. The most common causes of CVST include inherited thrombophilias (Factor V Leiden, Protein C/S deficiency, antithrombin deficiency), acquired hypercoagulable states (pregnancy, postpartum period, oral contraceptives, malignancy), inflammatory conditions (systemic lupus erythematosus, inflammatory bowel disease), infections (mastoiditis, sinusitis, meningitis), mechanical factors (head trauma, neurosurgical procedures), and dehydration 1. To investigate the cause, the following tests should be performed:
- Complete blood count
- Coagulation profile (PT, PTT, INR)
- Thrombophilia panel (Factor V Leiden, Prothrombin gene mutation, Protein C/S, antithrombin III levels)
- Antiphospholipid antibodies
- Homocysteine levels
- Inflammatory markers (ESR, CRP) Imaging studies should include:
- MRI with venography or CT venography to confirm the diagnosis and assess the extent of thrombosis 1 Additional tests may include:
- Lumbar puncture if infection is suspected
- Autoimmune panel for vasculitis or connective tissue disorders
- Cancer screening in patients with unprovoked thrombosis
- Drug screening for substances like cocaine that can cause CVST
- Genetic testing in patients with family history of thrombosis This comprehensive approach helps identify the underlying cause, which is crucial for determining appropriate treatment duration and preventing recurrence, as management differs significantly between transient risk factors like oral contraceptives versus permanent conditions like inherited thrombophilias.
From the Research
Causes of Cerebral Venous Sinus Thrombosis (CVST)
- CVST is a rare condition that can be caused by a combination of factors, including thrombosis of cerebral veins and increased intracranial pressure 2
- The underlying causes of CVST can be diverse, and a thorough history, ophthalmoscopic examination, laboratory studies, and imaging are necessary to determine the underlying cause 2
- Risk factors for CVST include oral contraceptive pills usage, chronic sinuses or ear infections, and obesity 3
- In some cases, the cause of CVST remains unclear, and conventional clotting tests may not be sensitive enough to detect prothrombotic conditions or mild haemostatic abnormalities 4
Investigations Used to Determine the Underlying Cause
- A combination of laboratory studies, including prothrombin time and activated partial thromboplastin time, can be used to evaluate the coagulation status of patients with CVST 4
- Imaging studies, such as computed tomography (CT) scan, magnetic resonance imaging (MRI), and magnetic resonance venography (MRV), can be used to diagnose CVST and determine the extent of venous sinus occlusion 3
- The calibrated automated thrombogram (CAT) assay is a physiological function test that can be used to detect minor aberrations in haemostasis and identify patients with a prothrombotic state 4
- A thorough history and physical examination, including ophthalmoscopic examination, can provide important clues to the underlying cause of CVST 2