Which chest findings may be observed in MG with respiratory involvement?

• A. Shallow breathing and diminished breath sounds
• B. Wheezing with crackles
• C. Hyperresonant breath sounds with no air entry
• D. Normal chest exam

Answer: (A)

Respiratory involvement in myasthenia gravis comes from weakness of the diaphragm and chest wall muscles, leading to reduced tidal volume and shallow breathing. Because air movement is limited, breath sounds can be diminished as ventilation is less effective and airway clearance is impaired, increasing the risk of atelectasis. Wheezing with crackles would suggest airway narrowing, secretions, or interstitial changes—not primarily neuromuscular weakness. Hyperresonant sounds with no air entry point would point to pneumothorax or a severe obstruction, which aren’t typical MG-related findings. A normal chest exam would be unlikely when respiratory muscles are impaired. So shallow breathing with diminished breath sounds best reflects MG with respiratory involvement.