Abrupt‐Onset Dementia: Differential Diagnosis and Clinical Characteristics of a Rare Condition

Cases of abrupt-onset dementia are rare overall and associated with a limited differential diagnosis. Evaluation of patients with abrupt-onset dementia should prioritize testing for vascular, autoimmune, infectious, and toxic causes. Early-recognition of patients with potentially treatment-responsive causes of dementia may promote earlier intervention leading to better outcomes in selected patients.