A 52-year-old man with a history of factor V Leiden thrombophilia, persistent headaches and papilloedema presented with worsening vision and confusion. MRI and MR angiography of the brain at the time of this presentation showed findings concerning for transverse sinus thrombosis and an associated dural arteriovenous fistula. Dural venous sinus thrombosis can lead to the formation of a dural arteriovenous fistula, which must be considered in the differential diagnosis for intracranial hypertension in patients with thrombophilia.
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A 52-year-old man presented with persistent headaches, worsening vision, confusion and papilloedema. He had a history of factor V Leiden thrombophilia and had been admitted 1 year earlier to an outside institution with similar symptoms. At that time, a standard MR scan of the brain without dedicated vascular sequences was interpreted as normal.
On this occasion, his MRI of the brain with MR angiography suggested a transverse sinus thrombosis with an associated dural arteriovenous fistula (figures 1 and 2A). These findings included:
dilated, serpiginous vascular structures within the posterior fossa (T2-weighted and contrast-enhanced MR angiogram images), suggesting venous congestion from a high-flow shunt;
flow-related enhancement in the sigmoid sinus during the arterial acquisition (time-of-flight MR angiography);
enhancement of multiple dural and cortical venous structures during the arterial phase (contrast-enhanced MR angiography);
suggestion of arterial feeders at the level of the thrombosed sinus.
Digital subtraction angiography confirmed the presence of a dural arteriovenous fistula at the suspected level in the thrombosed left sigmoid sinus, with feeders from the left external carotid and vertebral arteries, and retrograde drainage into the left transverse, straight and superior sagittal sinuses as well as dilated posterior fossa and perimedullary veins (figure 2B).
Dural venous sinus thrombosis can lead to the formation of a dural arteriovenous fistula,1 2 which must be considered in the differential diagnosis for intracranial hypertension in patients with thrombophilia. Once a dural arteriovenous fistula is formed, the high-flow shunt may result in abnormal retrograde flow into the dural sinuses or cortical veins, leading to venous hypertension with associated encephalopathy and risk of bleeding. This retrograde drainage results from the combination of a high flow within the dural arteriovenous fistula and a stenosis or complete occlusion of the venous sinus outflow. MRI features of retrograde flow such as flow-related or contrast-related enhancement in venous structures during the arterial phase acquisition, and especially the evidence of dilated cortical veins, strongly suggest a dural arteriovenous fistula and should prompt examination by conventional angiography. The presence of dilated cortical veins is associated with aggressive haemorrhagic or, less commonly, encephalopathic manifestations of this disease.2 3
Contributors Each of the contributing authors participated in image analysis, manuscript drafting and manuscript revision.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed. This article was reviewed by Robert Simister, London, UK.