Myasthenia gravis is a chronic neuromuscular disease resulting in skeletal muscle weakness, most commonly in the muscles in the eyes, face and those associated with the swallowing mechanism. It occurs due to a breakdown in communication between nerves and muscles. An estimated 36,000 to 60,000 people in the United States have the condition. 

Symptoms of myasthenia gravis include episodic instances of muscle weakness, drooping of one or both eyelids, altered speech, problems swallowing or chewing, and limited facial expressions. While most commonly associated with the face, it may also affect the neck and limb muscles. 

Myasthenia gravis may be exacerbated by fatigue, illness, stress and certain medications, such as beta blockers, some antibiotics and quinine. Patients with this disease may be more susceptible to certain other medical conditions, including an under or overactive thyroid and certain autoimmune conditions, for example rheumatoid arthritis or lupus. 

There is no cure for myasthenia gravis, but treatment can help patients manage the condition. Treatment may involve intravenous therapy, surgery, and medication using myasthenia gravis agents and certain antineoplastic monoclonal antibodies.