RESEARCH PAPER A multicentre prospective study of Guillain-Barré Syndrome in Japan: a focus on the incidence of subtypes Yoshiyuki Mitsui, 1 Susumu Kusunoki, 1 Kimiyoshi Arimura, 2 Ryuji Kaji, 3 Takashi Kanda, 4 Satoshi Kuwabara, 5 Masahiro Sonoo, 6 Kazuo Takada, 1 and the Japanese GBS Study Group ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ jnnp-2013-306509). 1 Faculty of Medicine, Department of Neurology, Kinki University, Osaka, Japan 2 Department of Neurology, Ookatsu Hospital, Kagoshima, Japan 3 Department of Neurology, Tokushima University Graduate School of Medicine, Tokushima, Japan 4 Department of Neurology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan 5 Department of Neurology, Chiba University Graduate School of Medicine, Chiba, Japan 6 Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan Correspondence to Professor Susumu Kusunoki, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, Japan 589-8511; kusunoki-tky@umin.ac.jp For Japanese GBS Study Group see online supplementary appendix. Received 7 August 2013 Accepted 3 November 2013 To cite: Mitsui Y, Kusunoki S, Arimura K, et al. J Neurol Neurosurg Psychiatry Published Online First: [ please include Day Month Year] doi:10.1136/ jnnp-2013-306509 ABSTRACT Objective Guillain–Barré Syndrome (GBS) is classified into the two major subtypes; acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Previous studies have suggested that AIDP is predominant and AMAN is rare in Western countries, whereas AMAN is not always uncommon in East Asia. We aimed to clarify the incidence of the subtypes of GBS in Japan. Methods We performed a prospective multicentre survey over 3 years (2007–2010). Clinical and electrophysiological findings were collected from 184 patients with GBS in 23 tertiary neurology institutes. Anti-ganglioside antibodies were measured by ELISA. We also surveyed the incidence of Fisher syndrome (FS). Results By electrodiagnostic criteria of Ho et al, patients were classified as having AIDP (40%), or AMAN (22%), or unclassified (38%). Anti-GM1 IgG antibodies were found for 47% of AMAN patients, and 18% of AIDP patients (p<0.001). There were no specific regional trends of the electrodiagnosis and anti-GM1 positivity. During the same study period, 79 patients with FS were identified; the percentage of FS cases out of all cases (FS/(GBS+FS)) was 26%. Conclusions The frequency of GBS patients with the electrodiagnosis of AMAN by single nerve conduction studies is approximately 20% in Japan, and the AMAN pattern is closely associated with anti-GM1 antibodies. The incidence of FS appears to be much higher in Japan than in Western countries. INTRODUCTION The concept of Guillain–Barré syndrome (GBS) changed in the 1990s due to the recognition of acute motor axonal neuropathy (AMAN) as an axonal subtype of GBS. 1–3 Thus, GBS is now divided into two major subtypes: AMAN and acute inflammatory demyelinating polyradiculoneuropa- thy (AIDP), mainly based on neurophysiological criteria. AMAN has been associated with ante- cedent Campylobacter jejuni infection and auto- antibodies to gangliosides, especially to GM1 and GalNAc-GD1a. 45 Previous reports have suggested that AIDP is frequent and AMAN is rare in Western countries, whereas AMAN is common in Asia and central and southern America. 2 3 6–18 Some regional studies in Japan 7–9 17 suggested that the frequency of AMAN seems to be higher than in Western countries (23–48%), but this has not been shown in a large nationwide prospective survey. In the current study, we examined the electrophysio- logical subtypes in a large prospective cohort of the Japanese population and compared these data with those from Western countries and China. METHODS Survey procedures To investigate the incidence of axonal GBS, a nationwide multicentre prospective survey of GBS was conducted by the Research Committees for Neuroimmunological Diseases sponsored by the Ministry of Health, Labor and Welfare, Japan. Data for patients with GBS that fulfilled Asbury and Cornblath 19 criteria were collected from 23 univer- sity hospitals or tertiary hospitals in the Japan GBS study group (see online supplementary appendix) between August 2007 and July 2010. In this period, 222 patients with GBS were treated at these hospi- tals. Of these patients, 184 gave informed consent for utilisation of personal data, storage and assay of biological materials for research purposes. Data for these 184 patients (male 114, female 70, age: 45.5 ±18.5) were collected prospectively and analysed. This is a large multicentre study in Japan. The number of patients with Fisher syndrome (FS) was also surveyed. FS was diagnosed based on clinical symptoms characterised by acute and self- limited ophthalmoplegia, ataxia and areflexia. 20 The study design was agreed upon and approved by the ethics committee of Kinki University Faculty of Medicine. Clinical information The following clinical information was prospect- ively collected for the 184 patients using predefined format: type of antecedent events (respiratory, gastrointestinal, others and none); GBS disability score 21 from 0 to 6 (at nadir and at 6 months after onset: 0, healthy; 1, minor symptoms or signs, able to run; 2, able to walk 5 m independently; 3, able to walk 5 m with a walker or support; 4, bed- bound or chair-bound; 5, requiring assisted ventila- tion; 6, death); sensory disturbance (yes or no); deep sensory disturbance (yes or no); cranial nerve palsy (yes or no); ophthalmoplegia (yes or no); facial nerve palsy (yes or no); and oropharyngeal palsy (yes or no). Mitsui Y, et al. J Neurol Neurosurg Psychiatry 2013;0:1–5. doi:10.1136/jnnp-2013-306509 1 Neuromuscular JNNP Online First, published on November 22, 2013 as 10.1136/jnnp-2013-306509 Copyright Article author (or their employer) 2013. 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