[Prognosis of patients with myasthenia gravis]

To study the correlation between therapy and outcome of patients with late adult onset and ocular type myasthenia gravis (MG).

The 58 MG patients admitted to our hospitals from 1991 to 2003 were classified into juvenile (younger than 20), early adult onset (20-64) and late adult onset (65 or older) groups, or also ocular and generalized types. We evaluated their therapeutic outcomes.

The late adult onset group consisted of 11 patients, classified as 4 ocular and 7 generalized types. There were more women than men in both the late and early adult onset groups. Anti-acetylcholine receptor (anti-AchR) antibodies were positive in all patients. Four patients had thymus lesions. Ten patients received treatment as follows: steroid therapy in 6, thymectomy in 4 and only choline-esterase (ChE) inhibitor therapy in 4 patients. However 4 patients worsened after treatment because of inadequate steroid therapy, 2 of whom experienced myasthenic crisis. On the other hand 21 patients were ocular type, of whom anti-AchR antibodies were positive in 12. They received treatments of the 21, steroid therapy was given to 12, thymectomy was performed in 4 and only ChE inhibitor therapy was given to 8 patients. One ocular type patient progressed to the generalized type. Six of 16 improved patients showed distinct recovery.

In the late adult onset group careful assessment concerning timings of administration and reduction of steroid are required to avoid side effects and complications. One ocular type patient progressed to the generalized type and most patients had a good outcome, which might be related to steroid therapy.