Ocular Myasthenia Gravis

Ahn, Suk-Won; Hong, Yoon-Ho

Korean Journal of Neuromuscular Disorders 2009;1(1):72-75.

Department of Neurology, Seoul National University College of Medicine Seoul National University Hospital1, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea

안구형 중증근무력증

안석원, 홍윤호

서울대학교 의과대학 서울대학병원 신경과1, 서울특별시 보라매병원 신경과

Abstract

Autoimmune myasthenia gravis (MG) frequently involves the extrinsic ocular muscles (EOM) and the disease clinically restricted to the EOM is referred to as ocular myasthenia (OMG). It has been reported that approximately 50% of patients presenting with OMG subsequently progress to develop generalized disease, usually within the first one to two years. Several clinical and laboratory factors, such as older age at onset, presence of anti-acetylcholine receptor (AChR) antibody, high antibody titers, and the presence of thymoma, have been claimed to predict the risk for secondary generalization. As for the treatment of OMG, early immunosuppressive therapy, specifically corticosteroids, has been suggested to prevent or delay the progression into generalized disease, although the cost-to-benefit ratio of this treatment remains controversial with no randomized controlled study conducted so far. There is mounting epidemilogical evidence of ethnic difference in clinical manifestation of MG, particularly between Caucasians and Asians. Asians appears to have an earlier childhood onset, higher prevalence of OMG, and lower titers of AChR antibody. This article should be focused on OMG, particularly regarding its definition, natural course, diagnostic and therapeutic challenges. Also it will be covered why EOM is susceptible to MG.