Outcome in juvenile-onset myasthenia gravis: a retrospective study with long-term follow-up of 79 patients

Abstract

Randomised and controlled treatment studies of juvenile-onset myasthenia gravis have not been published. We therefore report our retrospective analysis of 79 patients with juvenile-onset myasthenia gravis observed for as long as 30 years. The mean age at onset was 13.7 years and median follow-up 7.7 years. The initial presentation was generalised disease in 90% and ocular disease in the remaining patients. Sixty-five patients (82%) were thymectomised. In 14 of these, treatment consisted of a combination of azathioprine (2-3 mg/kg), corticosteroids (prednisolone up to 60 mg for a maximum duration of 12 months with subsequent tapering) and acetylcholinesterase (AChE) inhibitors, and of azathioprine and AChE inhibitors in 27 patients. One patient received azathioprine and 22 AChE inhibitors only; in another no further medication was necessary. In the severely affected group (n = 16), plasmapheresis was performed additionally before thymectomy and continued for some time after the operation. Treatment was started between 1 and 14 months (mean 2.4 months) after the onset of myasthenic symptoms. No thymectomy was done in 14 patients, and immunosuppressive treatment and AChE inhibitors were given in 9 of these cases. One patient received azathioprine only; 4 patients received AChE inhibitors only. The histology of the thymus gland showed follicular hyperplasia in 89% of the 65 thymectomised patients and normal findings in the remainder. Remission occurred in 60% of patients who underwent thymectomy and in 29% of those who were not thymectomised. Hyperthyroidism (6 patients, 8%), diabetes mellitus (2 patients, 3%) and rheumatoid arthritis (2 patients, 3%) were the most frequent associated immune-mediated diseases. Epileptic seizures and neoplasia were coincident diseases in 2 (3%) and 3 (4%) patients, respectively. There were no deaths from thymectomy or from immunosupression. This open, retrospective analysis suggests that juvenile-onset myasthenia gravis can be treated satisfactorily in most patients by the use of thymectomy and/or immunosupressive medication.

Clinical Characteristics of Pediatric Myasthenia: A Surveillance Study

“…Their patients presented mainly with ocular symptoms (84.3%) at a mean age of 4.1 years. 22 Compared with studies describing pediatric myasthenia from China, Korea, Jamaica, Europe, and India, [23][24][25][26][27] whose populations are more ethically uniform, the current study is unique in that the Canadian population is ethnically diverse. Consequently, the differences in terms of gender, age of onset, and subtype of myasthenia gravis likely reflect differences in the ethnic backgrounds and associated genetic susceptibility between the populations.…”

Juvenile myasthenia gravis

“…The incidence of juvenile patients who present with purely ocular symptoms (Osserman grade Ia) has been reported to range widely from 27% to 93% in retrospective analyses (Table 1). 4,5,13,17,22,28,29,36,41,43 The variability in presentation appears to be somewhat dependent upon ethnicity. Several studies of Asian children have reported a substantially higher incidence of ocular presentation.…”

Myasthenia gravis: past, present, and future

“…It has been utilized as a single immunosuppressant agent in MG since the 1970s, and large, retrospective reports support its efficacy (92). A randomized, double-blind trial demonstrated its efficacy also as a steroid-sparing agent.…”