CEREBRAL VENOUS THROMBOSIS

Created 07/04/2021, last revision 10/09/2023

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 the development of venous infarction
  • rupture of veins and capillaries → parenchymal hematoma
  • hematoencephalic barrier (HEB) disorder → 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 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, mental changes) and/or parenchymal lesion (venous infarct +/- hemorrhage) (focal neurological deficit, seizures)
  

• the most common symptom in CVST is a 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

• optic disc swelling (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 occurs 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  [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

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

• 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
• for a list of adverse prognostic factors, refer to the table and CVT risk score below)