Performance of c-NORSE Score in a Brazilian Cohort After Testing for Antineuronal Antibodies with Tissue-based and Cell-based Assays
João Henrique Ferreira1, Anna Maria Gomes1, Ana Carolina Zetehaku1, Taissa Ferrari Marinho1, Fabio Fieni Toso1, Caio Disserol1, Mariana Braatz Krueger3, Mara Lúcia Santos4, Aline Freire Borges Juliano5, Tércio Luz Barbosa6, Letícia Januzi Rocha7, Fernando Tenório Gameleira7, Renata Barbosa Paolilo8, Vanessa Daccach Marques9, João Pedro Gomes9, Katia Lin10, Adaucto Wanderley da Nóbrega Junior10, Emily Lima Marmentini10, Anderson de Cuffa11, Georgia Lelis Aranha Tavares12, Ronaldo Maciel Dias13, Sabrina Stephanie Lana Diniz14, Fábio Siquineli15, Pedro Braga-Neto16, Paulo Ribeiro Nobrega16, Lorena Pitombeira Sanders16, Fernanda Martins Maia Carvalho17, Renata Brasileiro Reis Pereira18, Eduardo Sousa de Melo19, Adélia Maria de Miranda Henriques-Souza20, Clecio de Oliveira Godeiro Junior21, Omar Gurrola Arambula22, Filipe Nolasco Souza e Silva23, Karla Oliveira Couto23, Dayane Danieli24, Katia Werneck Seitz25, Alessandra Dellavance26, Luis Eduardo Andrade26, Luis Caboclo2, Livia Dutra2
1Instituto do Cerebro, Hospital Israelita Albert Einstein, 2Neurology, Instituto do Cerebro, Hospital Israelita Albert Einstein, 3Neurology, Hospital Infantil Albert Sabin, 4Hospital Pequeno Príncipe, 5Universidade Federal do Maranhão, 6Universidade Federal do Piauí, 7Universidade Federal do Alagoas, 8Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, 9Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo, 10Universidade Federal de Santa Catarina, 11Hospital da UNIMED Grande Florianópolis, 12Grupo Hospitalar Conceição, 13Hospital de Base de Brasília, 14Universidade Federal de Minas gerais, 15Hospital Santa Isabel, 16Universidade Federal Do Ceara, 17Hospital Geral de Fortaleza, 18Hospital da Criança de Brasília José Alencar, 19Universidade Federal de Pernambuco, 20Instituto de Medicina Integral Professor Fernando Figueira, 21Universidade Federal do Rio Grande do Norte, 22Universidade Estadual de Mato Grosso do Sul, 23Hospital Santa Izabel, 24Universidade Federal do Mato Grosso do Sul, 25Hospital da Criança Augusta Muller Bohner, 26Grupo Fleury
Objective:
To describe a cohort of Brazilian NORSE patients and assess the sensitivity and specificity of a clinical score for early cryptogenic etiology prediction (c-NORSE score) after autoimmune encephalitis (AE) testing.
Background:
AE is a common cause of NORSE, but accurate estimates are lacking. Early recognition of NORSE etiology can impact treatment decisions.
Design/Methods:
Forty NORSE patients from the Brazilian Autoimmune Encephalitis Network (BrAIN) were investigated with brain MRI, CSF analysis, and TBA/CBAs for antineuronal antibodies (abs) in serum and CSF. Final diagnoses were compiled after chart review. Patients were divided into two groups by c-NORSE score: (≥5) high score (HS) or (<5) low score (LS), and clinical variables were compared. c-NORSE score sensitivity and specificity were calculated.
Results:
Of the 40 NORSE patients, 23 (57,5%) were children, 52% were female, 22.5% had AE, and 47.5% were c-NORSE. Eleven patients (27%) were in the HS group and 29 (73%) in the LS group. Bilateral and symmetric MRI findings were more frequent in HS group (HS 100% vs. LS 35%, p=0.003), while memory/behavioral symptoms were less common (HS 27% vs. LS 83%, p=0.002). All HS patients had c-NORSE, while 72% of the LS patients had other diagnoses, such as AE (n=9), HSV encephalitis (n=4), encephalomyelitis (n=1), ADEM (n=1), and other causes (n=5). The sensitivity of the c-NORSE score for predicting cryptogenic cases was 57.9% (95% CI: 36.3%-76.9%), and the specificity was 100% (95% CI: 84.5%-100%.
Conclusions:
In this cohort, most cases were cryptogenic and 22.5% had AE. C-NORSE score ≥5 was 100% specific for identifying cryptogenic cases, while a score <5 indicates further investigation is needed. Although the sensitivity of the c-NORSE was lower than previously reported, likely due to variations on complementary investigation performed, it remains a valuable bedside tool for NORSE evaluation in low-income countries with limited access to antineuronal abs testing.
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