Intracranial dural arteriovenous fistula is a rare cause of reversible vascular dementia, through a presumed mechanism of intracerebral venous hypertension. The clinical presentations are variable with no easily recognisable syndrome. It is a treatable and reversible cause of cognitive decline, unexplained otherwise. Often the sole presentation could be progressive cognitive decline to suggest a neurodegenerative dementia however the careful clinical history may give the clue of increasing intracranial pressure. Careful radiological review will help to intervene early to cure this condition. We report a case of 55 year old man who presented with progressive symptoms of pulsatile tinnitus for two years, with features of encephalopathy for six month and subsequent focal neurological symptoms and seizure. He was initially diagnosed as dementia and was later treated as stroke before he was referred to our centre. MRI scan of brain revealed dilated veins along the cerebral convexities and the brain stem with progressive diffuse white matter oedema. Cerebral angiography revealed a dural A-V fistula around the right transverse/sigmoid sinus. His history of familial hemochromatosis raises the suspicion of hyperviscosity induced venous thrombus as the putative cause. This was treated with onyx embolisation. His symptoms and the radiological abnormalities resolved completely.