Rapidly reversible dementia

Brain magnetic resonance imaging showed an abnormal pattern of flow voids in the region of the right transverse sinus (figure, A). Angiography showed a dural arteriovenous fistula of the right transverse sinus and torcula, with occlusion of the right sigmoid sinus. The fistula drained retrogradely into the deep cerebral venous system and into cortical veins (figure, B). Dye injected into the bilateral internal carotid arteries had an abnormally long transition time from the arterial to venous phase and did not opacify any dural sinuses, consistent with high pressure in these structures (35 mm Hg, normal 3-8, measured with an intra-sinus catheter). He had a partial endovascular embolisation of the fistula from both the venous and arterial sides. Although a small residual shunt remained, torcular pressure dropped to 28 mm Hg, and arterial-to-- venous transition time decreased. Cognitive function returned to normal after the procedure. He returned to full employment and functional independence within days. His pulsatile tinnitus disappeared, but migraine headaches persisted and were successfully treated with atenolol. A follow-up angiogram two years later, in Sept, 2002, showed no residual fistula.