Improved Neuromuscular Transmission Following Thymectomy in Juvenile Myasthenia Gravis: A Case Series

Introduction/Aims Juvenile myasthenia gravis (JMG) patients report symptomatic improvement following thymectomy; however, there is a lack of published literature on biomarkers for interval improvement. This study aimed to investigate the utility of single‐fiber electromyography to quantify changes post‐thymectomy. Methods This was a retrospective medical record review of JMG patients who underwent thymectomy at Children's Healthcare of Atlanta between 2014 and 2024. Pre‐ and post‐thymectomy orbicularis oculi jitter values and Myasthenia Gravis Activities of Daily Living (MG‐ADL) scores were recorded. A two‐sided paired t‐test was used to compare results pre‐ and post‐thymectomy and Pearson's correlations were calculated. Results Twelve JMG patients (6 female) with a mean age at diagnosis of 12.9 ± 4.5 (range 1.6–17.1) years, positive acetylcholine receptor antibodies, and normal thymus imaging underwent thoracoscopic thymectomy at 15.2 ± 3.3 (range 7.4–18.2) years. Post‐thymectomy, there was a statistically significant decrease in mean jitter (interval 7.3 ± 7.4 months, mean difference −33.2 ± 32.6 μs, p = 0.04, n = 7) and MG‐ADL scores (interval 2.5 ± 2.1 years, mean difference −2.2 ± 2.5, p = 0.02, n = 11). There were no significant correlations between timing of thymectomy after diagnosis and the change in mean jitter ( r = 0.11, p = 0.8, n = 7) and MG‐ADL ( r = −0.19, p = 0.58, n = 11). No major post‐surgical complications were observed. Discussion Thymectomy is well‐tolerated and leads to both objective and subjective improvement in JMG patients.