Dural venous sinus thrombosis
Dural venous sinus thrombosis is a subset of cerebral venous thrombosis, often coexisting with cortical or deep vein thrombosis, and presenting in similar fashion, depending mainly on which sinus is involved.
As such please refer to the cerebral venous thrombosis article for a general discussion.
Any age however women on the contraceptive pill are over represented.
Presentation is variable, and can range from asymptomatic to coma and death. Typically patients complain of headache nausea and vomiting. Neurological deficits are variable. The subsequent venous hypertension can lead to oedema, and even haemorrhage.
- hormones, e.g. oral contraceptive pill, pregnancy, puerperium, steroids
- prothrombotic haematological conditions, e.g. protein S deficiency, polycythaemia
- local factors, e.g. skull abnormalities / trauma, infections (especially mastoid sinus - dural sinus occlusive disease (DSOD))
- systemic illness, e.g. dehydration, sepsis, malignancy, connective tissue disorders
- idiopathic: ~ 12.5%
Any of the dural sinuses can be affected, in isolation or combined / continuous with one another.
- superior sagittal sinus thrombosis
- straight sinus thrombosis
- transverse sinus thrombosis
- sigmoid sinus thrombosis (including dural sinus occlusive disease (DSOD))
- cavernous sinus thrombosis
In a non-contrast CT, when not associated with venous haemorrhage or infarction it can be a subtle finding, relying on hyperdensity of the sinus being identified. Potential findings include:
- cord sign
dense vein sign
- a potential pitfall is interpreting the distal superior sagittal sinus as being hyperdense near the torcular herophili. The walls at this location can be thick, measuring upto 2-3mm.
- cerebral oedema - secondary to venous hypertension
- cortical / cerebral swelling
- unilateral or bilateral venous haemorrhage
With contrast administration, especially with a CT venogram, then a filling defect in a sinus is sought. When in the superior sagittal sinus it is referred to as the empty delta sign. Signs on contrast CT include:
- empty delta sign
- gyral enhancement
- prominent intramedullary veins
MRI is able to both visualise the clot as well as the sequelae. The clot acutely is isodense on T1 and hypo intense on T2 (this can mimic a flow void), with sub acute clot becoming hyper intense on T1. All the findings listed in the CT section are also seen on MRI.
MRV will demonstrate lack of flow.
- type 1 - no imaging abnormality
- type 2 - high T2
- type 3 - high T2 with enhancement
- type 4 - haemorrhage or infarction
Treatment and prognosis
Medical, with heparin and warfarin. Anticoagulation is usually required even in the setting of venous haemorrhage (see cerebral venous infarction).
Interventional management include microcatheter thrombolysis or thromboplasty.
- 1. Virapongse C, Cazenave C, Quisling R et-al. The empty delta sign: frequency and significance in 76 cases of dural sinus thrombosis. Radiology. 1987;162 (3): 779-85. Radiology (abstract) - Pubmed citation
- 2. Lee EJ. The empty delta sign. Radiology. 2002;224 (3): 788-9. doi:10.1148/radiol.2243990978 - Pubmed citation
- 3. Schell CL, Rathe RJ. Superior sagittal sinus thrombosis. Still a killer. West. J. Med. 1988;149 (3): 304-7. Free text at pubmed - Pubmed citation
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