RESUMEN
A 37-year-old man with anti-muscle-specific tyrosine kinase (MuSK) antibody-positive myasthenia gravis (MG) presented with subacute progressive dysphagia and muscle weakness of the neck and bilateral upper extremities. Conventional immune-suppressive treatments and high-dose intravenous immunoglobulin were ineffective. He then displayed repeated exacerbations and remissions over the course of two years, despite two to four sessions of plasma exchange (PE) every two months. The patient was successfully treated with outpatient periodic weekly blood purification therapy with alternative PE and double-filtration plasmapheresis using an internal shunt. This case report suggests the benefits of blood purification therapy with an internal shunt against anti-MuSK antibody-positive MG.