Demographic and Clinical Features of Ocular Myasthenia Gravis and Identification of Prognostic Factors: A Retrospective Study (P05.180)

Abstract

Objective: To study the demographic and clinical features of ocular Myasthenia Gravis (MG) and identification of prognostic factors. Background Ocular MG presents as binocular diplopia and ptosis with conversion rate to generalized MG varies from 40-75 %. There is no consensus on the diagnostic tests, treatment and outcome because of lack of good prospective trials. Design/Methods: Retrospective chart review. Results: Out of 345 patients who had 1245 follow up visits, who came to the university hospitals and clinics between 2000-2011 with myasthenia gravis, 75 patients were diagnosed with ocular MG based on clinical and one laboratory feature: acetylcholine receptor antibody (AchRAb), tensilon test, repetitive nerve stimulation (RNS) or Single-Fiber Electromyography (SFEMG). 12 patients converted to generalized MG within 3 years. Out of 63 patients with ocular MG, 30(47.6%) were males and 33(52.4%) females. Average age of onset was 56 ± 12.5 for both males and females. There were 43(68.2%) patients with age of onset above 55 years. 14(22.2%) patients were seropositive. 47(74.6%) patients required small dose steroid (less than 10 mg daily) while 6(9.5%) patients were on steroid sparing agents (Azathiprine or Mycophenolate Mofetil). 51(80.9%) patients have a follow up of at least 5 years. Out of 51 patients, 28(44.4%) patients were in remission on a very small dose of steroid. Age, sex, receptor antibody or early use of steroid did not have any impact of the prognosis including conversion to generalized MG. Conclusions: Ocular MG is a diagnostic challenge because of false negative AchRAb, repetitive nerve testing, tensilon test and difficult SFEMG (time consuming and not freely available). Most of the patients who present with ocular symptoms convert to generalized MG within 2 years. There is no correlation between the rate of conversion and age, sex, AchRAb or early use of steroid. This study has some limitation including small sample size. Disclosure: Dr. Singh has nothing to disclose. Dr. Neelam has nothing to disclose. Dr. Lim has nothing to disclose.