Cerebral Venous Sinus Thrombosis
- Cerebral venous sinus thrombosis (CVST) is a rare cerebrovascular disease that affects about 5 people per million and accounts for 0.5% of strokes.
- The diagnosis is often delayed or overlooked in the ED due to the diversity of clinical symptoms.
- Although rare, this presentation has an overall death and dependency rate of 15%.
- Deterioration after admission occurs in 23% of adult patients – with seizures, new focal deficits, or altered mental status.
- As such, it is an important consideration in patients presenting with headache to the ED.
- Most patients have multiple identifiable risk factors, however studies have shown that 12.5% of patients present with no risk factors at all.
- Risk factors can include: genetic and acquired prothrombotic disorders, medications (oral contraceptives, hormonal replacement therapy, steroids, oncologic treatments), malignancy, hematologic disease (polycythemia, thrombocytopenia, anemia), vasculitis, systemic inflammatory disorders, pregnancy and puerperium, infections (CNS, ear, sinus, mouth, face, neck), mechanical precipitants (lumbar puncture, cranial trauma, jugular catheter occlusion).
- CVST can present with a wide range of symptoms based on patient age, location of the thrombosis, and presence of associated parenchymal lesions.
- Most commonly patients present with headache, with a gradual onset.
- However, 2-13% of patients experience a thunderclap headache as a primary symptom.
- Focal neurologic deficits
- May be transient, patchy, and incongruent with isolated vascular territories
- An absence of neurologic deficit cannot rule out CVST
- More commonly, focal
- Altered mental status
- Ranging from confusion to coma
- Diagnosis requires a careful history, examination, and a high degree of suspicion.
- CVST must be considered in patients who present with a new or unique persistent headache, headache with insidious onset, or headaches that worsen with movement that increase intracranial pressure (ICP), such as coughing or bending over.
- Non-contrast CT head (NCCT) may demonstrate sequelae of CVST including hemorrhages, infarcts, and edema.
- May see a dense clot sign in the confluence of sinuses or focal cerebral edema in a region of single venous sinus drainage.
- NCCT head may be normal in 25% of patients with CVST.
- CT Angiogram (CTA)
- Depending on the timing of the contrast, CTA may visualize the arteries and the veins. However, this is highly dependent on local radiology protocols.
- CT Venogram (CTV) – Sensitivity ~90%, specificity ~95%.
- MR Venogram (MRV) – Sensitivity and specificity >95%.
- It is important to discuss with your local radiology department in order to help choose the best available imaging available.
- A recently published prospective multi-centre study in 2020 attempted to derive a new clinical score for CVST probability and increase the predictive value of that score by incorporating D-dimer levels.
- The score was derived including 6 variables: seizure at presentation (4), known thrombophilia (4), oral contraceptive use (2), symptoms greater than 6 days (2), worst headache ever (1), focal neurologic deficits (1) which stratified patients into low (0-2 points), moderate (3-5 points), and high risk (6-14 points) groups.
- 9% of patients had CVST in the low risk group, however when combined with negative D-dimer <500µg/L there were no misses of CVST.
- This clinical prediction rule has not yet been validated in the ED and the study is not generalizable to a Canadian context due to the high prevalence of CVST in the study population (26.2%) and the inclusion of patients who presented to neurology-specific EDs.
- Consultation to Neurology and/or Critical Care.
- Management goals include recanalization of the occluded sinus or vein, preventing propagation of the thrombus, and treating the underlying prothrombotic state.
- Systemic anticoagulation with heparin-based products even if there is presence of coexisting hemorrhage.
- Potential use of endovascular techniques with clot extraction/thrombolysis.
Take Home Points
- CVST is a rare, but serious, cause of headache and the diagnosis should be considered in any new or persistent headache or headaches with signs of increased ICP; a thorough history, physical exam, and high degree of clinical suspicion is required.
- NCCT may show sequelae of CVST, but can be normal ¼ of the time.
- Discuss imaging with the local radiology department to determine the best available scan (CTA, CTV, MRV).
- D-dimer has not yet been validated for use in risk stratification of CVST.
- Consult Neurology as the patient will get admitted for heparin-based therapies and observation.
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Due to the rarity of CVST, much of the literature is based mainly on single-centre or single-country studies. As such, the evidence is mixed from low to moderate quality. Multinational and multi-centre studies, such as the international study on cerebral vein and dural sinus thrombosis (ISCVT) has allowed for more robust evidence on the clinical presentation, risk factors, outcome, and prognosis in CVST.
Ferro, J. M., Canhao, P., Stam, J., Bousser, M.G., & Barinagarrementeria, F. (2004). Prognosis of Cerebral Vein and Dural Sinus Thrombosis – Results of the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT). Stroke, 35, 664-670. 10.1161/01.STR.0000117571.76197.26
Heldner, M. R., Zuurbier, S. M., Li, B., Von Martial, R., Meijers, J. C.M., Zimmerman, R., Volbers, B., Jung, S., El-Koussey, M., Fischer, U., Kohler, H. P., Schroeder, V., Coutinho, J. M., & Arnold, M. (2020). Prediction of cerebral venous thrombosis with a new clinical score and D-dimer levels. Neurology, 95, 898-909.
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by the BC Emergency Medicine Network and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. The BC Emergency Medicine Network is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. The BC Emergency Medicine Network also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Mar 15, 2021
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