Coexistence Of Anti-Musk-Positive Bulbar Myasthenia Gravis And Myotonic Dystrophy Type 1: The First Case Report from Turkey

Muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG) is an acute-onset subtype of MG that primarily affects the fasciobulbar muscles and begins with progressive velopharyngeal and respiratory symptoms such as early respiratory crises, swallowing, and speaking difficulties. Myotonic dystrophy Type 1 (DM1) is an autosomal dominantly inherited autoimmune neuromuscular disease characterized by distal-dominant muscle weakness, cardiovascular pathologies, and corneal disorders. In this case report, we discussed 42-year-old female patient with a previous diagnosis of DM1, and diagnosed with MuSK-MG as a result of electroneuromyographic and antibody tests upon the development of bulbar symptoms and thymus hyperplasia. The patient underwent video-assisted thymectomy, and medical treatment was started with a combination of pyridostigmine and methylprednisolone. The coexistence of anti-MuSK positive MG with thymoid hyperplasia and DM 1 has not been reported so far, and it has been predicted that both diseases may trigger each other through neuroinflammatory mechanisms on an autoimmunergic basis.