Myasthenia gravis: lessons for the emergency physician

We describe three patients with myasthenia gravis who presented to the emergency department - one with a previously established diagnosis and two others who were newly diagnosed as a result of workup initiated in the emergency department. Differential diagnosis of conditions causing neuromuscular weakness is broad; however, a key aspect of myasthenia gravis is fluctuating muscle weakness that increases with repeated use and improves with rest. Both newly diagnosed patients presented with ocular complaints, a common finding in myasthenia gravis. The third patient presented with a potentially life-threatening myasthenic crisis. Key points of discussion include: bedside tests to diagnose myasthenia gravis; distinction between cholinergic versus myasthenic crisis; and emergency department considerations when intubating a myasthenia gravis patient becomes necessary.