RT Journal Article
SR Electronic
T1 Nationwide survey of Lambert-Eaton myasthenic syndrome in Japan
JF BMJ Neurology Open
JO BMJ Neurol Open
FD BMJ Publishing Group Ltd
SP e000291
DO 10.1136/bmjno-2022-000291
VO 4
IS 2
A1 Hiroaki Yoshikawa
A1 Yumi Adachi
A1 Yosikazu Nakamura
A1 Nagato Kuriyama
A1 Hiroyuki Murai
A1 Yoshiko Nomura
A1 Yasunari Sakai
A1 Kazuo Iwasa
A1 Yutaka Furukawa
A1 Satoshi Kuwabara
A1 Makoto Matsui
YR 2022
UL http://neurologyopen.bmj.com/content/4/2/e000291.abstract
AB Background There was no nationwide epidemiological study of Lambert-Eaton myasthenic syndrome (LEMS) in Japan; therefore, we conducted a nationwide survey.Methods For the first survey, we sent survey sheets to randomly selected medical departments (n=7545) to obtain the number of LEMS who visited medical departments between 1 January 2017 and 31 December 2017. For the second survey, we sent survey sheets to the corresponding medical departments to obtain clinical information on LEMS.Results We received 2708 responses (recovery rate: 35.9%) to the first survey. We estimated the number of LEMS as 348 (95% CI 247 to 449). The prevalence was 2.7 (95% CI 1.9 to 3.5) in 1 000 000 population. As a result of the second survey, we obtained 30 case records of 16 men and 14 women. Fourteen patients (46.7%) had a tumour, and 10 out of 14 tumours were small-cell lung carcinoma (71.4%). There was a predominance of men in the LEMS with tumour (paraneoplastic LEMS, P-LEMS) (n=11, 78.6%) and women in the LEMS without tumour (a primary autoimmune form of LEMS, AI-LEMS) (n=11, 68.8%) (p=0.0136). The onset age (mean (SD)) for the P-LEMS was 67.1 (9.0), and that for AI-LEMS was 57.8 (11.2) years old (p=0.0103). The disease duration (median) for P-LEMS was 2 years, and for AI-LEMS was 7.5 years (p=0.0134).Conclusions The prevalence of LEMS in Japan is similar to that in other countries. There are predominances of men in P-LEMS and women in AI-LEMS.Data are available upon reasonable request. Data are available from the corresponding author upon reasonable request.