Rapidly progressive cognitive impairment, ataxia, and myoclonus: an unusual presentation of a dural arteriovenous fistula.

Dural arteriovenous fistulas (DAVFs) have a wide range of clinical presentations, including dementia associated with white matter changes (WMCs). We report a case of DAVF presenting as a rapid progressive dementia and myoclonus without WMCs. A 64-year-old hypertensive and diabetic man was admitted because of a 3-month history of progressive cognitive decline, extrapyramidal and cerebellar signs, and myoclonus. Magnetic resonance imaging (MRI) scans of the brain showed dilated cerebellar veins and T2WI hypersignal in the basal ganglia without WMCs. After admission, he suffered sequential bilateral deep intracerebral hemorrhages. A repeated angioMRI disclosed thrombosis of the distal sagittal and the proximal lateral sinuses. Angiography revealed a torcullar region DAVF. Embolization of the dural fistula was performed. On follow-up, the patients' cognitive deficits improved and myoclonus disappeared. The clinical picture may be explained by venous hypertension in the deep venous system, producing bilateral basal ganglia/thalamic dysfunction and in the posterior fossa. This case shows that DAVFs can produce subcortical dementia without involvement of the deep white matter.