Once Myasthenic, Always Myasthenic? Observations on the Behavior and Prognosis of Myasthenia Gravis in a Cohort of 100 Patients

Background: The natural history of myasthenia gravis [MG] is unpredictable: In the first few years the disease course is worst with subsequent gradual disease stabilization. However, some patients tend to have continued disease activity or resurgence of the disease many years into the illness. The factors correlating with disease course need further evaluation.

Aims: To study the patterns of remissions, worsening and exacerbations in patients with MG and correlate various factors affecting them.

Settings And Design: Retrospective, Institute Review Board (IRB) approved study in tertiary referral neurology center.

Materials And Methods: Hundred patients with acquired MG confirming the inclusion criteria were studied. Pharmacological remissions, complete stable remissions, exacerbations, worsening episodes were analyzed with respect to age of onset, disease extent, disease severity at onset and worst of illness, acetyl choline receptor antibody positivity, thymectomy status, period of disease, pharmacotherapy and crisis episodes.

Results And Conclusions: In this cohort the percentage of new remission rates per year steadily declined after the first year. Ocular myasthenia had lesser clinical worsening episodes and high chance of complete stable remission. Generalized disease had less chance drug free remission. The risk of episodes of worsening persisted at a steady rate over a period of time, being maximum in the first year. The risk of exacerbations was unpredictable and could occur after prolonged clinical quiescence, often was related to reduction of immunosuppression. The disease course did not differ significantly in the juvenile and adult age-groups. There was a strong case for permanent immunomodulation in MG.