Psychoses as the presenting manifestation of Creutzfeldt-Jakob disease in an elderly male.

The differential diagnosis of acute psychosis includes delirium, dementia and primary psychiatric disorders. A comprehensive medical evaluation is crucial to make the proper diagnosis. We report the case of a healthy elderly man who presents with acute psychosis. We describe our diagnostic evaluation based on the patient's history and physical examination, which identified Creutzfeldt-Jakob disease. Avoiding diagnostic error in patients who face such a rapidly progressive and catastrophic illness is paramount.