Evaluation of incidence and clinical features of antibody-associated autoimmune encephalitis mimicking dementia.
BACKGROUND
Anti-neuronal autoimmunity may cause cognitive impairment that meets the criteria for dementia. Objective. Our aim was to detect the incidence and clinical features of autoimmune encephalitis imitating clinical findings of primary dementia disorders and to delineate the validity of anti-neuronal antibody screening in dementia patients.


METHODS
Fifty consecutive patients fulfilling the clinical criteria for primary dementia, 130 control patients, and 50 healthy controls were included. Their sera were investigated for several ion channel and glutamic acid decarboxylase (GAD) antibodies by a cell-based assay, radioimmunoassay, and ELISA, as required.


RESULTS
Sixteen patients satisfying dementia criteria had atypical findings or findings suggestive of autoimmune encephalitis. N-methyl-D-aspartate receptor (NMDAR) antibody was detected in a patient with dementia, Parkinsonism, and REM sleep behavior disorder (RBD) fulfilling the criteria for dementia with Lewy bodies (DLB). One control patient with bipolar disease displayed low anti-GAD antibody levels.


CONCLUSIONS
Our study showed for the first time the presence of parkinsonism and RBD in an anti-NMDAR encephalitis patient mimicking DLB. Although autoimmune encephalitis patients may occasionally present with cognitive decline, most dementia patients do not exhibit anti-neuronal antibodies, suggesting that routine analysis of these antibodies in dementia is not mandatory, even though they display atypical features.
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Millet Caddesi, Capa, 34390 Istanbul, Turkey.
Arzu
A
Çoban
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Cem
C
Ismail Küçükali
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Millet Caddesi, Capa, 34390 Istanbul, Turkey.
Başar
B
Bilgiç
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Nazlı
N
Yalçınkaya
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Hazal
H
Haytural
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Canan
C
Ulusoy
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Selin
S
Turan
Department of Psychiatry, Istanbul Faculty of Medicine, Istanbul University, 34390 Istanbul, Turkey.
Sibel
S
Çakır
Department of Psychiatry, Istanbul Faculty of Medicine, Istanbul University, 34390 Istanbul, Turkey.
Alp
A
Uçok
Istanbul Erenkoy Psychiatric and Neurological Disorders Hospital, 34736 Istanbul, Turkey.
Hüseyin
H
Ünübol
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Millet Caddesi, Capa, 34390 Istanbul, Turkey.
Hasmet A
HA
Hanagasi
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Millet Caddesi, Capa, 34390 Istanbul, Turkey.
Hakan
H
Gürvit
Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, 34093 Istanbul, Turkey.
Erdem
E
Tüzün
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D003704:Dementia / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004660:Encephalitis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D005260:Female; D050031:Hashimoto Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged