Abstract
BACKGROUND AND PURPOSE: Rapidly progressive dementia (RPD) represents a heterogeneous group of clinical dementia syndromes characterized by a precipitous decline in cognitive function, typically occurring over weeks to months, with diverse underlying etiologies. To elucidate the evolving etiological spectrum of RPD and investigate temporal trends, we conducted a comprehensive systematic review incorporating temporal subgroup analyses. METHOD: English-language studies published prior to December 31, 2024 were searched in the Medline (PubMed), ISI Web of Science and the Cochrane Library databases. Study design, study period, patient characteristics, etiologies of RPD in each study were retrieved. RESULT: We encompassed 13 studies in our final systematic review, involving a total of 1,701 patients with RPD. Our findings revealed that neurodegenerative diseases (459 cases, 27.0%), neuroimmune diseases (327 cases, 19.2%), and central nervous system infections (295 cases, 17.3%) represented the most prevalent etiological categories associated with RPD. Among distinct disease entities, autoimmune encephalitis (AE, 266 cases, 15.6%), Alzheimer's disease (214 cases, 12.6%), and Creutzfeldt-Jakob disease (214 cases, 12.6%) were identified as the three most frequently observed etiologies of RPD. Temporally, neuroimmune diseases, particularly AE, exhibited a significant upward trend in prevalence over the study period. CONCLUSION: These findings highlight the evolving etiological spectrum of RPD and emphasize the need for ongoing research and targeted diagnostic strategies to address the rising incidence of neuroimmune-related RPD.