Clinical features of myasthenia gravis in southern China: a retrospective review of 2,154 cases over 22 years.

The objectives of the study are to study the clinical features of myasthenia gravis in southern China. A retrospective study was carried out on all patients who were diagnosed with myasthenia gravis at the First Affiliated Hospital of Sun Yat-sen University during 1987-2009. Of the 2,154 myasthenia gravis patients, the gender ratio (male:female) was 1:1.15. The median age at onset was 18 years. There was a single peak distribution of age at onset, and 44.8 % were children (≤ 14 years) at first onset. 1,766 patients (82.0 %) only had ocular symptoms at onset. 1,451 patients (67.4 %) were classified as Osserman grade I. 250 unselected patients received anti-acetylcholine receptor antibodies test, in which only 51.2 % were positive. Computed tomography scan/magnetic resonance Imaging of chest were done in 1,354 patients, of which 899 patients (66.4 %) had thymic hyperplasia and 201(14.8 %) had thymoma. There were 150 patients (7.0 %) with myasthenia gravis combined with other autoimmune diseases, in which hyperthyroidism was most common (84 %). 189 (8.8 %) patients experienced 267 episodes of crisis. The rate of family myasthenia gravis was 1.6 % (35/2,154). In conclusion, the clinical features and demography of myasthenia gravis patients in this study are significantly different from prior studies on other regions and ethnic groups.