Abstract
Isolated respiratory failure due to myasthenia gravis that selectively involved the respiratory muscles alone is extremely rare and difficult to diagnose. We reported herein, a 46 year old patient who presented with acute respiratory failure, 4 weeks after thymoma resection. The respiratory failure was due to myasthenia gravis that selectively affected the respiratory muscles only without having any peripheral signs. The initial response to therapy with pyridostigmine was unexpectedly complicated with severe bradycardia that made insertion of permanent pacemaker essential, before further therapy.