CEREBRAL VENOUS SINUS THROMBOSIS
Diagnosis of cerebral venous thrombosis
Created 07/04/2021, last revision 29/04/2023
- diagnosis is often difficult in the initial stages; the time course and symptoms are variable and nonspecific
- focal symptoms occur in association with the development of venous infarcts
- exclude CVT in the presence of:
- intracranial hypertension syndrome
- atypical ischemia – especially with atypical localization, not respecting arterial territories, and with hemorrhagic component or edema
- first epileptic seizure (especially in young women)
- direct signs of thrombosis on NCCT
Neuroimaging
- neuroimaging is essential for the diagnosis of CVT
- CT is widely available and is the most commonly used baseline imaging modality
When should you think about cerebral venous sinus thrombosis?
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Direct signs of thrombus in the vein/dural sinus | |
Indirect signs
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CT + CT venography
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MRI + MR venography
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Digital subtraction angiography
- consider possible anatomical variants of the venous system, including hypoplasia or absence of some of the vessels
- specific for CVST diagnosis is the “stop sign” (abrupt termination of a sinus or vein) with collateral circulation and congestion of cortical veins (dilation, tortuosity)
- it may show associated cortical veins thrombosis and possibly arterio-venous fistula and deep vein thrombosis
- in addition, DSA shows the dynamics and drainage pattern in the occluded area
- after applying the contrast agent, the venous system is completely visualized within 7-8 seconds
- in thrombosis, the filling of the veins is delayed or absent
- currently, MRV and CTV dominate the diagnostic workup, and DSA is reserved for interventional procedures when conservative therapy fails
Neurosonology
- low sensitivity and specificity; the method may be suitable for treatment monitoring
- we mostly evaluate indirect signs – flow acceleration (> 40 cm/s) due to collateral circulation
- the sigmoid sinus (SS) thrombosis can be monitored by examining flow in the ipsilateral internal jugular veins (IJV)
- more about TCCD examination of cerebral veins and sinuses see here
Further diagnostic studies
D-dimers
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Lumbar puncture
- perform lumbar puncture if an infectious etiology is suspected
- CSF evacuation may relieve pain or prevent loss of vision (20-30 ml of CSF)
- typical signs of venous thrombosis include increased opening pressure, proteinorhachia, and sometimes mild pleocytosis
- mild pleocytosis may lead to misdiagnosis of neuroinfection
- lumbar puncture is contraindicated in the presence of an expansive parenchymal lesion
Other laboratory studies
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EEG
- pathological findings tend to occur with parenchymal lesions
- in mental status is altered, rule out nonconvulsive status epilepticus (NCSE)
Differential diagnosis
- high-flow dural A-V fistula can lead to venous congestion with hemorrhagic infarction (which can difficult to distinguish from a venous thrombosis)
- headaches and encephalopathy are uncommon in ischemic stroke
- infarct lesions in ischemic stroke and CVST differ in shape and location
- in CVST, hemorrhagic transformation and collateral edema are common on baseline imaging
- look for signs of inflammation – fever, leukocytosis with ↑CRP and ↑ESR
- positive CSF findings (pleocytosis, elevated protein level)
- consider a combination of venous thrombosis and neuroinfection (in such case, thrombosis is probably triggered by the infection)
- typical symptoms and signs: headache, facial nerve palsy
- exclude venous thrombosis (MRV/CTV)
- symptoms not typical for IIH:
- encephalopathy
- focal neurological deficits
- seizures