Zilucoplan for Successful Early Weaning From Mechanical Ventilation and Avoiding Tracheostomy in an 85-Year-Old Woman Experiencing Myasthenic Crisis: A Case Report

Myasthenic crisis is a life-threatening exacerbation of myasthenia gravis leading to respiratory failure, while zilucoplan is a C5 complement inhibitor that prevents complement-mediated destruction of the neuromuscular junction, thereby helping to restore muscle function and respiration. This case report describes an 85-year-old woman with late-onset myasthenia gravis who developed myasthenic crisis triggered by aspiration while eating. Initial treatment with Intravenous immunoglobulin and intravenous methylprednisolone showed limited efficacy, making weaning from mechanical ventilation challenging. Due to her advanced age, diabetes, and heart failure, plasmapheresis was considered high-risk. Zilucoplan, a C5 inhibitor administered subcutaneously, was introduced as an adjunctive therapy on Day 11, leading to rapid 50% hemolytic complement activity level reduction and significant muscle strength improvement. Extubation was achieved within four days, avoiding tracheostomy. Add-on therapy of zilucoplan provided a safe and accessible treatment option for myasthenic crisis. Previous reports have demonstrated the benefits of other C5 inhibitors and neonatal Fc receptor inhibitors in refractory myasthenic crisis. This case supports the early addition of zilucoplan with conventional rescue therapies for myasthenic crisis may have enabled earlier extubation and the avoidance of tracheostomy. Further studies are needed to determine the universal applicability of add-on therapies in myasthenic crisis, considering comorbidities and complications.