Myasthenia gravis: a retrospective study comparing thymectomy to conservative treatment

To study the effectiveness of thymectomy (TY) in a group of patients with myasthenia gravis compared to a group of patients submitted to conservative treatment (CT) at a similar clinical stage.

Among 153 patients with myasthenia gravis, we paired 28 patients who underwent TY, with 28 cases under CT. The following data were analyzed: gender, age, and age at the beginning of symptoms, illness duration, follow-up time and type of medical treatment. There was no statistical difference between these 2 groups. The mean time for TY was 2.5 (0.2-13) years after the onset of the disease. The cases were evaluated through a functional scale at the beginning and at the end of the study.

We found complete remission in 15 cases (TY 6, CT 9), improved (normal life with or without minimal symptoms and with or without medication) 9 cases (TY 8, CT 1), improved with partial control and minimal limitation 32 cases (TY 14, CT 18), and poor control 2 cases (TY 2). No death was found in this group.

There was no statistical difference between the conservative treatment and thymectomy groups, regarding remission or improvement. Furthermore TY done in the first year of the disease or latter, did not change the final outcome.