Ventilator-Associated Pneumomediastinum With Secondary Pneumothorax in Myasthenic Crisis.

Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction that can progress to myasthenic crisis, a life-threatening condition requiring mechanical ventilation. While ventilatory support is essential, it carries the risk of barotrauma, including pneumomediastinum and pneumothorax. We present the case of a 58-year-old female with a history of MG who developed acute hypercapnic respiratory failure requiring intubation and mechanical ventilation. Her clinical course was complicated by pneumomediastinum with associated subcutaneous emphysema and a secondary pneumothorax identified on CT imaging following a prolonged intensive care stay. The pathophysiology of ventilator-associated barotrauma involves alveolar overdistension and rupture, allowing air to track along bronchovascular sheaths into the mediastinum (Macklin effect), with potential extension into the pleural space and subcutaneous tissues. In this case, contributing factors likely included prolonged mechanical ventilation, underlying bronchiectasis with paraseptal bullous changes, and immunosuppression. The patient was managed conservatively with close monitoring and multidisciplinary care, resulting in clinical stability without the need for surgical intervention. This case highlights a rare but clinically significant complication of mechanical ventilation in myasthenic crisis and underscores the importance of early recognition of barotrauma. Awareness of this potential complication is essential for timely diagnosis and appropriate management in critically ill patients with MG.