CEREBRAL VENOUS THROMBOSIS

Created 07/04/2021, last revision 22/01/2023

Introduction

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

• 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!

• 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  
  • optic disc swelling is caused by an increased intracranial pressure
  • present in 50-60% of intracranial thrombosis cases, most pronounced in thrombosis of the sagittal and cavernous sinus (SC)
  • papilledema poses a risk of permanent loss of vision!
• focal neurological deficits approx. in 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 (NCSE)
    
• visual field disturbances (in case of the Labbe vein involvement)
• epileptic seizures (in approx. 40% of patients, often with Todd’s hemiparesis)
• rarely does sinus thrombosis initially manifest as a subarachnoid hemorrhage [Sharma, 2010] [Oppenheim, 2005]
  • rupture of 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 helpful to include MRV in the diagnostic workup
• obstructive hydrocephalus – rare complication
  • usually caused by an intraventricular extension of thalamic hematoma caused by the thrombosis of internal veins

Late complications

• chronic headaches
• post-CVST seizures
• recurrence of CVST
• visual loss
• dural arteriovenous fistula
  • the consequence of persisting sinus occlusion with increased venous pressure
  • preexisting DAVF can be the cause of CVST

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 is, 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)