Table 2.

RPD aetiologies in routine clinical practice and specialist referral centres

Study	Definition of RPD	Number of patients	Inflammatory (%)		Neurodegenerative (%)			Neurovascular (%)	Toxic–metabolic (%)	Other (%)
			Infectious	Immune-mediated	CJD	AD	Other
Tertiary centre
Acosta et al. (2020)35	First symptom to dementia: ≤2 years	104	3	23	30	9	19	3	6	8
Anuja et al. (2018)26	First symptom to dementia: ≤1 year	187	21	18	8	14 (AD or other)		10	16	13
Neto et al. (2017)a (ref.24)	First symptom to MMSE score <20: ≤2 years	61	20	46	12	8 (AD or other)		Counted as ‘other’	Counted as ‘other’	15
Zhang et al. (2017)34	First symptom to dementia: ≤2 years	310	26	9	7	15	10	Excluded	10	23
Sala et al. (2012)b (ref.33)	First symptom to dementia: ≤1 year	49	2	4	31	14	23	8	8	12
Papageorgiou et al. (2009)b (ref.25)	First symptom to dementia ≤1 year	68	6	9	13	18	29	13	Excluded	12
Outpatient memory clinic
Day et al. (2018)c (ref.28)	First symptom to dementia: ≤2 years	67	Counted as ‘other’	Counted as ‘other’	6	66	27	Counted as ‘other’	Counted as ‘other’	5
Single-centre CJD surveillance
Chitravas et al. (2011)6	Initially suspected prion disease	304	5	9	NAd	51	12	12	2	10
Grau-Rivera et al. (2015)31	Initially suspected prion disease	52	8	13	NAd	29	23	13	6	8
Maat et al. (2015)32	Initially suspected prion disease	181	4	12	NAd	34	17	11	1	21
Peckeu et al. (2017)30	Initially suspected prion disease	483	8 (infectious or immune-mediated)		NAd	36	12	9	10	25
Multicentre CJD surveillance
Stoeck et al. (2012)29	Initially suspected prion disease	7,115	11e (infectious or immune-mediated)		NAd	16	24	11	7	31

In tertiary centres and the outpatient clinic, diagnoses were based on clinical criteria^{24–26,28,31,33}, whereas diagnosis in CJD surveillance centres was fully^6,30–32 or partially²⁹ based on neuropathology. AD, Alzheimer disease; CJD, Creutzfeldt–Jakob disease; MMSE, Mini-Mental State Examination; NA, not applicable; RPD, rapidly progressive dementia. ^aDelirium was an additional exclusion criterion. ^bAdditional exclusion criteria: acute cognitive disturbance associated with infections, metabolic disorder and intoxication. ^cAdditional inclusion criteria: increase of more than two Clinical Dementia Rating stages in ≤2 years. ^dOwing to selection bias, prion diseases were not considered for this table. ^eParaneoplastic disease and CNS neoplasia were not differentiated (both classed as ‘other’).