Epidemiological and Clinical Characteristics of Myasthenia Gravis in Korea

J Korean Neurol Assoc > Volume 15(4); 1997 > Article

Journal of the Korean Neurological Association 1997;15(4): 825-838.

한국인 중증근무력증의 역학 및 임상적 특성 연구

이광우, 김지수, 이성현, MG연구회

서울대학교 의과대학 신경과학교실

Epidemiological and Clinical Characteristics of Myasthenia Gravis in Korea

Kwang Woo Lee, M.D., Ji Soo Kim, M.D., Sung Hyun Lee, M.D., and MG Study Group

Department of Neurology, College of Medicine, Seoul National University

Abstract

Background and Objectives; Myasthenia gravis(MG) is a disease of neuromuscular transmission associated with the autoimmune mechanism. The clinical and epidemiological characteristics of MG in Korea may be different from those in western countries. Method: Total 755 patients from the 20 general hospitals were included in this study. The type of onset was classified to ocular, bulbar, limb and generalized. The classification of clinical status was done by using the modified Osserman's method. Age of onset, sex, type of onset, associated disease, clinical course and other clinical features were studied. Resuts : Of the 755 patients, 282(37.4%) were male and 473(62.6%)were female. The mean age of onset was 32.5±19.4 years in male and 30.8±17.3 in female. The most common type of onset was ocular(60.7%). The generalized onset was observed in 27.5%, bulbar onset in 6.6%, limb onset in 5.2%. The duration from symptom onset to diagnosis varied from several days to 29 years(mean; 21.1 months). The clinical status was classified to ocular type in 29.5%, mild generalized in 19.1%, moderate generalized in 34.6%, acute fulminating in 5.0% and late severe in 11. 7%. There were 12 congenital and 2 neonatal type. Thirteen patients(1.7%) had family history of MG. The history of thyroid disease was present in 82 patients(10.9%), rheumatoid arthritis in 6(0.8%), SLE in 4(0.5%) and IDDM in 18(2.4%). Rheumatoid factor was positive in 8.0% and FANA in 21.8%. Tensilon test was positive in 92.7%, Jolly test in 78.6%. Chest CT revealed thymic abnormalities in 38.6%. I.e. thymic hyperplasia in 14.1% and thymoma in 24.5%. Anti-AChR antibodies were detected in 77.2%. Anticholinesterase therapy was tried in 76.2% and immunosuppressants were needed in 39.3%. Thymectomy was done in 175 patients(23.2%).
Conclusion: In Korean MGs, the mean age of onset was younger and ocular type MG was more common, compared those with western MGs. We could not find any significant difference in the mean age of onset between male and female.