A Case of Myasthenia Gravis Diagnosed After Hospitalization in a Patient Receiving Home Oxygen Therapy for Respiratory Failure.

INTRODUCTION

Respiratory failure has various causes, including neuromuscular disorders. We report a case of myasthenic crisis requiring intensive care after a delayed diagnosis.

CASE PRESENTATION: A woman in her 70s had been on home oxygen therapy for 10 months due to dyspnea. She was admitted with worsening dyspnea, type II respiratory failure, and pneumonia requiring mechanical ventilation. Although her pneumonia improved, ventilator weaning was unsuccessful. Muscle weakness raised suspicion of neuromuscular disease. Myasthenia gravis was a differential diagnosis, but she showed no thymoma, ocular symptoms, or abnormal findings on edrophonium or repetitive nerve stimulation tests. On Day 19, she tested positive for MuSK antibodies and myasthenia gravis was diagnosed. She was treated with prednisone, tacrolimus, intravenous immunoglobulin, and plasmapheresis. She was successfully weaned from mechanical ventilation and discharged home on hospital Day 81.

CONCLUSION

Myasthenia gravis should be considered as a differential diagnosis of unexplained respiratory failure.