Myasthenia Gravis (MG) is the largest group of neuromuscular junction disorders and has an annual incidence of 4-12 cases per 1 million annually. MG is characterized by auto-antibodies targeted against the acetylcholine receptor (AChR) or functionally related molecules at the post-synaptic membrane, leading to complement mediated lysis and decreased AChR activity. Although MG presentation may vary based on involved muscle groups, it presents with fatigable muscle weakness, typically involving extraocular muscles causing asymmetric ptosis and diplopia. Bulbar and respiratory musculature involvement can lead to life-threatening respiratory failure during myasthenic crises. Treatment is aimed at symptomatic relief and disease control. Intravenous immunoglobulin (IVIg) and plasmapheresis can be used as short-term treatments for acute respiratory insufficiency. Long term treatment options include acetylcholinesterase inhibitors for symptomatic relief, and thymectomy with immunosuppressive agents for disease control, including corticosteroids or non-steroidal immunosuppressive agents. More recently, immunomodulatory agents, such as C5a inhibitors and neonatal Fc receptor inhibitors (Nipocalimab), have received approval.
In contrast to generalized MG, treatment recommendations for Juvenile Myasthenia Gravis (JMG) are limited. Here we report a 13 year old LatinX patient with diagnosis of JMG and high AChR titers who, in contrast to experiencing minimal change with IVIg and steroid therapies, achieved rapid and sustained disease control with thymectomy followed by Nipocalimab infusion. To our knowledge, this is the first reported case of a pediatric patient receiving Nipocalimab following thymectomy. Our patient is of LatinX descent, an ethnic group underrepresented in the Vivacity Trial. While literature in the JMG space is limited, several studies have identified health disparities in Hispanic non-white individuals compared to the general population, including earlier age of presentation and increased chance of acute care re- hospitalization. While further studies examining health care disparities in JMG are needed, this case illustrates the efficacy of thymectomy with Nipocalimab for disease control in JMG.