title: Clinicopathological Correlations and Concomitant Pathologies in Rapidly Progressive Dementia: A Brain Bank Series.
abstract: BACKGROUND
  Rapidly progressive dementia (RPD) is caused by a heterogeneous group of both neurodegenerative and non-neurodegenerative disorders. The presence of concomitant pathologies, mainly Alzheimer's disease (AD), may act as a confounding variable in the diagnostic process of this group of diseases.
  
  
  OBJECTIVE
  We aimed to describe clinicopathological features, including Alzheimer's co-pathology, and diagnostic accuracy in a postmortem series of RPD.
  
  
  METHODS
  Retrospective analysis of 160 brain donors with RPD (defined as 2 years of disease duration from the first symptom to death) registered at the Neurological Tissue Bank of the Biobanc-Hospital Clínic-IDIBAPS, from 2001 to 2011.
  
  
  RESULTS
  Prion diseases were the most frequent neuropathological diagnosis (67%), followed by non-prion neurodegenerative pathologies (17%), mostly AD and dementia with Lewy bodies, and non-neurodegenerative diseases (16%). We observed clinicopathological diagnostic agreement in 94% of the patients with prion RPD but only in 21% of those with non-prion RPD. Four patients with potentially treatable disorders were diagnosed, while still alive, as having Creutzfeldt-Jakob disease. Concomitant pathologies were detected in 117 (73%). Among all RPD cases, 51 presented moderate or frequent mature β-amyloid plaques (neuritic plaques), which are considered to be associated with positive amyloid biomarkers in vivo.
  
  
  CONCLUSIONS
  Prion diseases were accurately identified in our series. In contrast, non-prion RPD diagnosis was poor while the patients were still alive, supporting the need for better diagnostic tools and confirmatory neuropathological studies. The presence of concomitant AD pathology in RPD should be taken into account in the interpretation of amyloid biomarkers.
authors.affiliation: Alzheimer's Disease and Other Cognitive Disorders Unit, Department of Neurology, Hospital Clx00ED;nic, Barcelona, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Grau-Rivera
authors.forename: Ellen
authors.initials: E
authors.lastname: Gelpi
authors.forename: Carlos
authors.initials: C
authors.lastname: Nos
authors.forename: Carles
authors.initials: C
authors.lastname: Gaig
authors.forename: Isidro
authors.initials: I
authors.lastname: Ferrer
authors.forename: Albert
authors.initials: A
authors.lastname: Saiz
authors.forename: Albert
authors.initials: A
authors.lastname: Lladó
authors.forename: José L
authors.initials: JL
authors.lastname: Molinuevo
authors.forename: Francesc
authors.initials: F
authors.lastname: Graus
authors.forename: Raquel
authors.initials: R
authors.lastname: Sánchez-Valle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D000682:Amyloid / Q000378:metabolism*; D001921:Brain / Q000473:pathology*; D007562:Creutzfeldt-Jakob Syndrome / Q000175:diagnosis / Q000473:pathology*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011328:Prions / Q000378:metabolism*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000682:Amyloid; D011328:Prions