CEREBRAL VENOUS THROMBOSIS

Clinical presentation and etiology of cerebral venous thrombosis

Updated on 20/01/2024, published on 07/04/2021

Introduction

  • cerebral venous sinus thrombosis (CVST) refers to the presence of a thrombus in the dural venous sinuses, which are responsible for draining blood from the brain
  • CVST accounts for approx. 1-2% of all strokes, with women being affected in 70% of cases
  • when diagnosed early and managed adequately, CVST generally has a favorable prognosis
  • the diagnosis of early stages can be challenging, primarily due to the highly variable and non-specific clinical manifestations
  • thrombosis results in intracranial hypertension and/or venous infarction (with or without a hemorrhagic component)
  • unrecognized venous thrombosis was formerly 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
Territories of cerebral veins and dural sinuses

Etiology

  • the most common causes:
  • combination of multiple factors is commonly observed
  • in ~ 10-37% of cases, no obvious risk factor or etiology is identified

Risk factors

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Pathophysiology

  • venous thrombosis impairs venous drainage → increased intravenous and intracapillary pressure
  • consequences:
    • impaired perfusion → cytotoxic edema and the development of venous infarction
    • rupture of veins and capillaries → parenchymal hematoma
    • blood-brain barrier (BBB) dysfunction → vasogenic edema
    • impaired cerebrospinal fluid (CSF) absorption

intracranial hypertension

  • in the absence of focal symptoms and with clinically predominant intracranial hypertension syndrome accompanied by papilledema, the diagnosis of pseudotumor cerebri (benign intracranial hypertension) can only be established after the careful exclusion of cerebral 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 (causing headache or mental changes) and/or parenchymal lesion (venous infarct +/- hemorrhage), manifesting as focal neurological deficit or seizures
  • the most common symptom in CVST is headache (80-90%), often accompanied by nausea and vomiting
    • isolated intracranial hypertension syndrome occurs in 20-40% of cases
    • symptoms typically worsen during Valsalva maneuvers (coughing, sneezing, or bending over)
    • there is no clear correlation between the location of pain and the site of thrombosis
    • the headache in CVST can mimic tension-type or migraine headaches, making diagnosis challenging in the absence of focal symptoms
  • papilledema  Papilledema
    • impaired vision; papilledema carries the risk of permanent vision loss!
    • present in 50-60% of intracranial thrombosis cases, most pronounced in thrombosis involving the sagittal and/or cavernous sinuses
  • altered level of consciousness or encephalopathy

    • rapid deterioration of consciousness indicates either decompensated intracranial hypertension or extension of thrombosis into the deep venous system; herniation syndromes may occur
    • disturbances of consciousness in the initial stages are usually due to deep venous involvement (with typical bithalamic involvement)
    • always consider the possibility of nonconvulsive status epilepticus (NCSE) 
  • focal neurological deficits occur in approx. in 50% of patients (in more advanced stages when ischemia or hemorrhage has developed) – a sudden worsening is probably caused by hemorrhagic transformation of ischemia
  • visual field disturbances (in cases involving the Labbe vein)
  • epileptic seizures (in approx. 40% of patients, often accompanied by Todd’s hemiparesis)
    • common, especially in cortical vein involvement
  • sinus thrombosis rarely presents initially as a subarachnoid hemorrhage  SAH as consequence of a cerebral venous thrombosis [Oppenheim, 2005] [Sharma, 2010] [Oppenheim, 2005]
    • rupture of dilated feeding veins due to retrograde intravenous hypertension
    • secondary rupture of the hemorrhagic venous infarct into the subarachnoid space
    • ⇒ in a small SAH with no detectable aneurysm, it is helpful to include MRV in the diagnostic workup
  • obstructive hydrocephalus
    • a rare complication
    • usually caused by an intraventricular extension of a thalamic hematoma caused by the thrombosis of internal veins
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Late complications

Prognosis

  • cerebral venous thrombosis generally has a more favorable prognosis than that of arterial strokes, particularly when diagnosed and treated promptly
  • various factors influence outcome:
    • extent of the thrombosis
    • rapidity of onset
    • appropriate treatment
    • presence of complicating factors such as hemorrhagic conversion or elevated intracranial pressure
  • according to the ISCVT study (International Study on Cerebral Vein and Dural Sinus Thrombosis)
    • 57.1% of patients were symptom-free (mRS=0), 22% had minor residual symptoms (mRS=1)
    • 7.5% had mild impairments (mRS=2), 5.1% were moderately or severely impaired (mRS=3-5)
    • 8.3% had died (mRS=6)
    •  seizures ~ 10.6% of patients
    • risk of recurrence ~ 2.2%
  • according to various studies, mortality in the acute phase is 0.4-13%
  • risk of deterioration in the first week after admission ~ 23%
  • recanalization: 84% at 3 months and 85% at 12 months (De Sousa, 2018)
    • positive predictors of recanalization are the female sex and thrombosis of the superior sagittal sinus
  • for a list of adverse prognostic factors, refer to the 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
Other risk factors
male sex
age > 37 y
initial coma (GCS)
severe neurological deficit
encephalopathy
seizures
rapid progression
intracerebral hemorrhage
extensive thrombosis involving multiple sinuses or deep venous systems
venous infarction with hemorrhagic component
malignancy
CNS infection
coagulopathy
sepsis
systemic inflammation
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Clinical presentation and etiology of cerebral venous thrombosis
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