CEREBRAL VENOUS THROMBOSIS

Clinical presentation and etiology of cerebral venous thrombosis

Created 07/04/2021, last revision 25/08/2022

Introduction

  • cerebral venous sinus thrombosis (CVST) means the presence of a thrombus in the dural venous sinuses, which drain blood from the brain
  • CVST accounts for about 1-2% of all strokes (women are affected in 70% of cases)
  • early diagnosed and adequately treated CVST has a good prognosis
  • diagnosis of early stages may be difficult mainly because of the highly variable and non-specific clinical manifestation
  • thrombosis results in intracranial hypertension and/or venous infarction (with or without hemorrhagic component)
  • unrecognized venous thrombosis used to be a common cause of misdiagnosed “pseudotumor cerebri”

The most common sites of symptomatic thrombosis:

  • transverse sinus
  • sigmoid sinus
  • superior sagittal sinus
  • deep venous system
  • straight sinus
  • cavernous sinus
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Etiology

  • genetically associated hypercoagulable state ~ 22%
  • combination of multiple factors is common
  • in approx. 10-15% of cases, no obvious risk factor is identified

Risk factors

Pathophysiology

  • venous thrombosis impairs venous drainage → increased intravenous and intracapillary pressure
  • consequences:
    • impaired perfusion → cytotoxic edema and development of venous infarction
    • rupture of veins and capillaries → parenchymal hematoma
    • HEB disorder → vasogenic edema
    • impaired CSF absorption

intracranial hypertension

  • in the absence of focal symptoms and clinically predominant intracranial hypertension syndrome with papilledema, the diagnosis of pseudotumor cerebri (benign intracranial hypertension) can be established only after careful exclusion of venous thrombosis!

Clinical presentation

  • search for the provoking conditions (listed in the table above) in the patient’s personal history
  • signs and symptoms result from intracranial hypertension (headache) and/or parenchymal lesion (focal neurological deficit, seizures)
  • the most common symptom in CVST is a headache (80-90%) with nausea and vomiting
    • isolated intracranial hypertension syndrome occurs in 20-40% of cases
    • typically worsens by Valsalva maneuver (coughing, sneezing, bending over)
    • there is no clear relationship between the location of pain and the site of thrombosis
  • papilledema   Papilledema
    • optic disc swelling caused by increased intracranial pressure
    • present in 50-60% of intracranial thromboses, most pronounced in thrombosis of the sagittal and cavernous sinus (SC)
    • papilledema poses a risk of permanent loss of vision!
  • focal neurological deficit in approx. 50% of patients (in more advanced stages when ischemia or hemorrhage develops) – a sudden worsening is probably caused by the bleeding into ischemia
  • qualitative and/or quantitative alteration of the level of consciousness
    • rapid progression of impaired consciousness indicates either decompensated intracranial hypertension or thrombosis progression into the deep venous system
    • disturbances of consciousness in the initial stages are usually due to deep venous involvement (with typical bithalamic involvement)
    • always exclude nonconvulsive status epilepticus
  • visual field disturbances (in case of the Labbe vein involvement)
  • epileptic seizures (in approx. 40% of patients, often with Todd’s hemiparesis)
  • rarely, sinus thrombosis initially manifests as a subarachnoid hemorrhage SAH as consequence of a cerebral venous thrombosis [Oppenheim, 2005] [Sharma, 2010] [Oppenheim, 2005]
    • rupture of a dilated feeding veins due to a retrograde intravenous hypertension
    • secondary rupture of the infarcted venous infarct into the SA space
    • ⇒ in a small SAH with no aneurysm detected, it is useful to include MRV in the diagnostic workup
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Prognosis

  • cerebral venous thrombosis has a good prognosis if diagnosed and treated early
  • according to the ISCVT study (International Study on Cerebral Vein and Dural Sinus Thrombosis)
    • full resolution is seen in 79% of patients, mRS 2: 7.5%, severe residual deficit (mRS 3-5) : 5%
    • mortality 8.3%
    • epilepsy ~ 10% of patients
    • risk of recurrence 2.2%
  • mortality in the acute phase according to different studies 0.4-13%
  • risk of deterioration in the first week after admission ~ 23%
  • recanalization: 84% at 3 months, 85% at 12 months
  • for adverse prognostic factors, see table and CVT risk score below)   CVT risk score (Ferro 2009)  CVT risk score (Ferro 2009)
Unfavorable prognostic factors
Demographic data
Clinical presentation and course
Imaging methods
Risk factors
male sex
age > 37 yrs
initial coma
severe neurological deficit
encephalopathy
seizures
intracerebral hematoma
thrombosis of the straight sinus and deep veins
venous infarction with hemorrhagic component
malignancy
neuroinfect
coagulopathy
sepsis
systemic disease
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