Myositis in H1N1 Infection Compounds to Myasthenic Crisis

Abstract

Infection is an important trigger of myasthenic crisis (MC), and those infections manifest with pneumonia and muscle involvement may result in more frequent MC. We report two myasthenia gravis (MG) patients with H1N1 infection, and highlight the reasons for deterioration. Two patients with MG had H1N1 infection. The diagnosis of MG was confirmed by neostigmine, repetitive nerve stimulation, and anti-acetylcholine receptor antibody tests. H1N1 was confirmed by nucleic acid detection study, and myositis by creatinine kinase. The patient with pneumonia and myositis had MC needing mechanical ventilation for 10 days, and the other patient without myositis did not have MC. They were treated with oseltamivir 75 mg twice daily for 5 days, and the patients with MC received ceftriaxone intravenously. Both the patients were on prednisolone and azathioprine, and none received prior H1N1 vaccination. The lady with MC with myositis was discharged on day 27 in wheelchair bound state, and the other one patient without myositis or MC was discharged on 6th day with full recovery. These patients highlight the need for evaluation for myositis along with pneumonia in the MG patients with H1N1 infection. Vaccination in MG patients on immunosuppression may be useful.