A reversible cause of "vascular dementia".

A 63-year-old woman presented with progressive dementia over 2 years. Plain head CT demonstrated dilated parenchymal vessels and vascular channels in the left occipital bone (figure 1, A and B). Angiography confirmed a dural arteriovenous malformation (dAVM) centered on the left sigmoid sinus with reflux into all venous sinuses (figure 1, C and D). Cerebral venous drainage was rerouted via cortical veins. Coil occlusion of the recipient venous pouch restored normal venous drainage and reduced the caliber of cortical veins (figure 2, A and B), helping improve cognitive function. Dementia secondary to dAVMs results from venous hypertension causing ischemic neuronal dysfunction.1 Fistula obliteration may reverse the dementia.