Juvenile myasthenia gravis: a case series review

Resumo

 Juvenile myasthenia gravis (JMG) is an autoimmune disease of the neuromuscular junction that affects children and adolescents under 18 years of age and can pose life risk. The clinical characteristics in Brazilian children have been barely described. A descriptive and retrospective study was carried out on 2024 to outline the clinical profile of patients with JMG at a neuromuscular disease center in Rio de Janeiro. Among the 11 eligible patients, there was a predominance of females (72.7%), with initial clinical manifestations at 5 years old. The most commonly observed initial form of disease presentation was ocular (45,5%), followed by bulbar form (27,3%), myasthenic crisis (18,2%) and muscular form (9,1%). The most frequent signs and symptoms through follow-up were ptosis (100%), muscle weakness (54,5%), dysphagia (45,4%), dysphonia (18,1%) and facial paresis (18,1%). Patients with ocular-onset disease experienced no disease progression, remaining with strictly ocular symptoms. In contrast, those with bulbar-onset developed limb weakness, and the single muscular-onset case developed ocular involvement, as all patients did at some point. Most patients had positive anti-acetylcholine receptor antibodies (72,7%) and none had anti-Musk antibodies. All patients used a cholinesterase inhibitor and only one (9%) did not require associated corticosteroids for disease improvement. Six patients (54.5%) had never had a myasthenic crisis, while 5 patients (45.5%) had at least one. Among those who did, all responded to human immunoglobulin and corticosteroid pulse therapy. Approximately one third (36,3%) required other immunosuppressants to control exacerbations. The majority have a normal thymus (72,7%), with thymectomy indicated for only one patient. Asthma is the most prevalent autoimmune comorbidity (27,2%), as is anxiety as a neuropsychiatric comorbidity (27,2%). At our neuromuscular disease center in Brazil, our patient profile is very similar to the descriptions made so far of patients with JMG.