Evolving Causes of Rapidly Progressive Dementia A 5-Year Comparative Study

Background: Rapidly progressive dementia (RPD) is a clinical syndrome developing in <1 to 2 years. Recent progress in RPD evaluation is significant, so RPD's prevalence may change over time. The aim of our new case series was to estimate the relative frequency of RPDs' causative entities, considering the recent advances in RPDs' diagnosis, and compare the results with those of our previous report. Patients and Methods: We retrospectively reviewed the medical records of 47 patients who were referred to Attikon University Hospital during a 5-year period for a suspected RPD. Results: Neurodegenerative diseases were the most frequent causes (38%), followed by prion disease (19%) and autoimmune encephalopathy (AE, 17%). AE cases were by far more common than in our previous report, while other than AE secondary causes were significantly decreased. Mean time to dementia was 9 months in neurodegenerative diseases and 5 months in non-neurodegenerative. Main clinical findings across all patients were memory impairment (66%) and behavioral-emotional disturbances (48%). Conclusions: Neurodegenerative diseases are common causes of RPD and have a slower evolution than non-neurodegenerative. Diagnostic novelties enabled the recognition of AE, whereas more common secondary causes are probably now diagnosed in primary settings since the recognition of RPD as distinct clinical entity is continually increasing.