Nivolumab-related myasthenia gravis with myositis requiring prolonged mechanical ventilation: a case report.

Nivolumab-induced severe myasthenia gravis with myositis and myocarditis required intensive care and prolonged mechanical ventilation. Although immune checkpoint inhibitor-related myasthenia gravis is a rare adverse event, appropriate and prompt treatment is required because of its severity and rapid progression. Diaphragm ultrasound was useful not only in diagnosing diaphragm dysfunction and deciding the strategy for weaning from mechanical ventilation but also in evaluating the recovery of the diaphragmatic function.