26PTherapeutic outcomes and prognostic determinants in juvenile myasthenia gravis

Juvenile myasthenia gravis (JMG) is a rare autoimmune neuromuscular disorder characterized by onset before 18 years of age. Although it shares clinical similarities with adult myasthenia gravis (MG), differences exist in disease severity, antibody profiles, and thymic pathology. This study aimed to evaluate therapeutic outcomes and identify predictors of clinical response in JMG patients treated at a single tertiary care center. A retrospective observational analysis was conducted on inpatient records of JMG patients with symptom onset at ≤18 years, admitted between 1999 and 2020. Prepubertal onset was defined as ≤12 years. Clinical and demographic data were analyzed, with treatment outcomes assessed according to the Myasthenia Gravis Foundation of America (MGFA) guidelines. A good outcome was defined as achieving complete stable remission, minimal manifestations, or clinical improvement. Sixty JMG patients (63.3% female) with a mean age of onset of 11.4 years were followed for an average of 7 years (range 1–22). At initial presentation, 56.6% exhibited generalized symptoms. Anti-acetylcholine receptor and muscle-specific kinase antibodies were positive in 68.5% and 5% of cases, respectively. Prepubertal onset was observed in 33 patients, with ocular symptoms being significantly more prevalent in this group compared to post-pubertal group (66.7% vs. 14.8%, p<0.001). Three patients with ocular onset progressed to generalized myasthenia when assessed at follow up. Immunotherapy was administered to 71.6% of patients, with all receiving glucocorticoids and 38.3% receiving steroid-sparing agents. Thymectomy was performed in 47.5% of cases, with no thymomas identified. A good outcome was achieved in 83.3% of patients, while 15% had suboptimal outcomes, including one fatality due to immunosuppressant-related toxicity. Crisis at presentation was noted in three post-pubertal patients, and relapse rates (16 patients) were similar across prepubertal and post-pubertal groups. Ocular MG (OMG) patients responded significantly better to acetylcholinesterase inhibitors alone (p=0.036), though overall treatment responses did not differ between ocular and generalized groups or between prepubertal (78.8%) and post-pubertal (88.8%) patients. More than three-quarters of patients with JMG achieved good outcomes. OMG was associated with earlier age of presentation and good response to acetylcholinesterase inhibitors alone, with outcomes comparable to generalized myasthenia.