Overview Snapshot A 58-year-old male presents with difficulties in concentration and worsening insomnia. These symptoms have been progressively worsening over the past month. Startle myoclonus is appreciated on physical examination. Electroencephalography shows biphasic sharp wave patterns. Introduction Prions login to view 4 more bullets Spongiform encephalopathy login to view 4 more bullets Presentation Symptoms login to view 7 more bullets Evaluation Histology login to view 2 more bullets Electroencephalography login to view 1 more bullet Cerebral spinal fluid (CSF) login to view 1 more bullet Magnetic resonance imaging login to view 1 more bullet Differential Alzheimer disease Frontotemporal dementia Vascular dementia HIV-associated dementia Treatment Supportive No effective treatment Prognosis, Prevention, and Complications Prognosis login to view 1 more bullet Prevention login to view 4 more bullets Complications login to view 2 more bullets