Myasthenia gravis: disease severity and prognosis

Abstract

Objectives: To examine myasthenia gravis (MG) severity and long-term prognosis in seronegative, seropositive, and thymoma MG.

Materials and methods: Four series of patients were studied retrospectively. Severity and treatment were assessed each year, and muscle antibodies were assayed.

Results: Seropositive MG patients had a more severe course than seronegative MG patients. MG severity was higher in non-thymectomized compared to thymectomized early-onset MG patients. MG severity did not differ between thymectomized and non-thymectomized late-onset patients. There was no significant difference in MG severity between thymoma and non-thymoma MG patients.

Conclusions: MG is more severe in seropositive MG patients. With proper treatment, especially early thymectomy, the long-term prognosis is good in seropositive MG patients. The present studies indicate a benefit of thymectomy in early-onset MG, but no dramatic benefit in late-onset MG. Similar MG severity and outcome was seen in thymoma and non-thymoma MG.