Clinical Outcomes and Treatment Efficacy in Juvenile Myasthenia Gravis: A Retrospective Review From a Single Center

Early recognition and treatment are critical in juvenile myasthenia gravis (JMG), yet pediatric-specific evidence remains limited. We aimed to describe treatment patterns, remission rates, and predictors in a Canadian cohort.

We conducted a retrospective study of patients under 18 years diagnosed with JMG at The Hospital for Sick Children, Toronto, between 2015 and 2025. Clinical, treatment, and outcome data were collected. Diagnosis was confirmed by antibody positivity or electrophysiology, and outcomes were classified using the Myasthenia Gravis Foundation of America postintervention status (MGFA-PIS). Kaplan-Meier and Cox regression analyses were used to evaluate remission and its predictors.

Thirty-six patients were included, 16 with generalized MG (GMG) and 20 with ocular MG (OMG). Mean age at diagnosis was 8.7 years; 50% were female. Acetylcholine receptor-positive, muscle-specific kinase-positive, and seronegative MG accounted for 55.6%, 5.6%, and 38.9% of the cohort, respectively. Repetitive nerve stimulation was abnormal in 82.6% tested. Most patients received pyridostigmine and corticosteroids initially, with additional immunosuppressants in selected cases. Seven received rituximab, and seven underwent thymectomy, with most achieving complete stable remission (CSR). The estimated 3-year remission rate was 36.1%, and 66.7% achieved CSR at last follow-up (median 45.5 months). Older age at onset and early immunosuppression predicted remission, while GMG had a higher rate than OMG (56.2% vs. 20.6%, p = 0.044).

Earlier immunosuppression was associated with a higher remission rate, whereas treatment tended to be initiated later and remission was less frequent in OMG. These findings support a timely treatment approach in JMG.