Clinically Worsening Myasthenia-Related Respiratory Distress Notwithstanding Normal Markers of Respiratory Function

An 81-year-old female with a past medical history of myasthenia gravis presented to the Emergency Department with difficulty breathing. At presentation, the patient also complained of fatigue, diplopia, and ptosis. Vitals and laboratory tests were largely benign. The patient was diagnosed as having a myasthenia gravis exacerbation, which eventually advanced to myasthenic crisis, with the patient requiring admission to the intensive care unit and supplementation of high-flow oxygen. Throughout the course of the patient's hospitalization, the measurements of her negative inspiratory force and vital capacity were found to be normal and unchanged despite shifting and unsteady respiratory symptoms. This uncommon case seeks to highlight the importance of complementing clinical context with the markers of respiratory function to assess the status of myasthenia-related respiratory distress.