Intracranial dural arteriovenous fistulas (DAVFs), constituting approximately 10 to15% of intracranial vascular malformations, are anomalous direct connections between dural arteries and venous sinuses, meningeal veins, or cortical veins; the arterial feeders are various, usually fed by branches of internal carotid, external carotid, or vertebral artery (Santillan et al. CNN 115(3):241-251, 2013; Holoekamp et al. JN 124(6):1752-65, 2016; Terada T et al. JN 80(5):884-9, 1994). Spectrums of clinical presentations are widespread, arranging from pulsatile tinnitus to intracranial hemorrhage. Such DAVFs with rapidly progressive dementia as primary presentation, which has been reported in several literature, are still extremely scarce (Santillan et al. CNN 115(3):241-251, 2013; Holoekamp et al JN 124(6):1752-65, 2016). Up to 2015, similar reports are less than 20 cases (Holoekamp et al. JN 124(6):1752-65, 2016). Herein, we report a patient who was misdiagnosed with encephalitis, presented thalamic dementia, and was ultimately diagnosed of DAVFs.