Suspected Bulbar-Predominant Myasthenia Gravis Exacerbation in an Older Adult With Respiratory Deterioration and Silent Aspiration: A Case Report.

Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction characterized by fluctuating skeletal muscle weakness. Bulbar-predominant exacerbations may be difficult to recognize in older adults with multiple comorbidities, particularly when respiratory deterioration is initially attributed to cardiopulmonary disease. We report the case of an 83-year-old woman with generalized acetylcholine receptor antibody-positive MG, dementia with behavioral disturbance, moderate chronic obstructive pulmonary disease (COPD), chronic kidney disease, and previous deep vein thrombosis who was admitted to a psychiatric unit because of worsening paranoia and suspected delusions. During hospitalization, she developed progressive hypoxemia requiring transfer to the medical ward. Initial evaluation considered pulmonary infection, aspiration-related complications, and COPD exacerbation. Neurological examination subsequently demonstrated new predominantly facial and bulbar weakness with preserved limb strength, accompanied by progressive dysphagia and impaired secretion clearance. Videofluoroscopic swallow study demonstrated significant silent aspiration of thin and mildly thickened liquids; however, the etiology of the dysphagia and aspiration remained potentially multifactorial. Serial arterial blood gases demonstrated persistent hypercapnia; however, stable PaCO₂ values, preserved pH, markedly elevated bicarbonate, and positive base excess suggested a substantial chronic hypercapnic component with concomitant metabolic alkalosis, with underlying COPD representing an important potential contributor. In the context of known generalized MG and newly documented facial and bulbar dysfunction, a suspected bulbar-predominant myasthenic exacerbation was considered a potentially important contributor within a multifactorial respiratory deterioration rather than the sole cause. She was treated with intravenous immunoglobulin and escalation of corticosteroid therapy. Although her respiratory status stabilized, persistent bulbar dysfunction, dysphagia, and frailty remained, and following goals-of-care discussions, the family elected hospice care. This case emphasizes the diagnostic complexity of respiratory deterioration in older patients with MG and the importance of recognizing new bulbar dysfunction while carefully considering competing pulmonary, aspiration-related, cardiogenic, and functional contributors.