A 50-year-old gentleman, with no previous comorbidities, presented with difficulty in neck holding, double vision, and ptosis of 2½ year duration. Repetitive nerve stimulation (RNS) and neostigmine test were suggestive of MG. Anti-AChR was negative. The patient was started on steroids, pyridostigmine, and azathioprine. Contrast-enhanced computed tomography (CECT) scan of the chest was normal. He improved symptomatically but never had complete remission. After 1½ years, he had worsening of symptoms associated with difficulty in chewing and swallowing, slurring of speech, and breathing difficulty. A diagnosis of myasthenic crisis was made, and the patient was given five cycles of plasma exchange with no improvement in symptoms. Anti-MuSK antibody was positive. He was started on intravenous (IV) rituximab (375 mg/m2) weekly for 4 weeks, and the symptoms gradually improved. After 2 weeks of initiation of treatment, the breathing difficulty resolved, and ptosis, diplopia, and neck holding improved after the next 2 months. Steroids and azathioprine were tapered and stopped. He is doing well currently at 24 months of follow-up after three cycles of rituximab and is planned for another cycle.
A 47-year-old gentleman presented a with 2-year history of bilateral ptosis, diplopia, and bulbar weakness. Neostigmine test and RNS were positive, while CECT of the chest was normal. Anti-AChR antibody was negative. Symptoms responded to steroids, pyridostigmine, and azathioprine. He was well for the next 2 years when he had developed severe bulbar weakness and respiratory difficulty. Anti-MuSK was positive, and five cycles of plasma exchange were administered with no response. IV rituximab was then started with good response after two doses, steroids and immunomodulation were tapered, and rituximab was given weekly for 4 weeks every 6 months. He is symptom free on 2-year follow-up.