Personalized Management and Timing of Thymectomy in Juvenile Myasthenia Gravis: Insights from Routine Clinical Scale Use in a Single-Center Retrospective Cohort—A Case Series

TL;DR

This study explores how using specific clinical scales can help personalize treatment for juvenile myasthenia gravis, a rare autoimmune disease in children.

Contribution

The study demonstrates the utility of routine clinical scales in guiding personalized treatment decisions for juvenile myasthenia gravis.

Findings

Thymectomy reduced QMG scores in 70% of patients, though relapses persisted.

Chronic IVIG therapy was linked to higher QMG scores and used in severe cases.

QMG and PM-QOL15 scores strongly correlated, reflecting disease burden.

Abstract

Introduction: Juvenile myasthenia gravis (JMG) is a rare autoimmune disorder with a variable clinical course and limited pediatric-specific treatment guidelines. Objective clinical scales, such as the Quantitative Myasthenia Gravis (QMG) Score and the Pediatric Myasthenia Gravis Quality of Life 15 (PM-QOL15), may support individualized management, but their role in routine practice remains underexplored. Methods: We retrospectively reviewed 10 seropositive JMG patients followed at a single tertiary neuromuscular clinic between 2014 and 2024. All patients underwent a systematic assessment with QMG at each visit, while PM-QOL15 was administered at the final visit. Clinical data, comorbidities, antibody status, treatment modalities, and outcomes were analyzed. Associations between treatment strategies, comorbidities, and scale scores were explored using appropriate statistical methods. Results: Seven patients (70%) underwent thymectomy, resulting in a reduction in mean QMG scores from 7.7 to 2.4, though residual relapses were observed. Chronic intravenous immunoglobulin (IVIG) therapy, administered to 70% of patients, did not significantly reduce relapse rates or steroid exposure and was associated with higher QMG scores in the second year, suggesting use in more severe phenotypes rather than therapeutic efficacy. Prolonged corticosteroid therapy did not improve remission time or relapse frequency and was complicated by major adverse effects in two patients. Timing of azathioprine initiation showed no significant correlation with relapse frequency. PM-QOL15 correlated strongly with mean QMG (r = 0.88, p < 0.001), reflecting cumulative disease burden. Patients with comorbidities required longer stabilization, although differences were not statistically significant. Conclusions: The routine integration of QMG and PM-QOL15 into follow-up may facilitate the earlier recognition of subclinical deterioration, provide objective measures of treatment response, and guide personalized management in JMG. Thymectomy showed benefit in selected patients, while the long-term roles of IVIG and corticosteroids remain uncertain. Larger multicenter prospective studies are warranted to confirm these findings and refine evidence-based strategies for pediatric JMG.

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