Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of the skeletal (voluntary) muscles of the body.It is caused by a defect in the transmission of nerve impulses to muscles.The symptoms include eye muscle weakness, eyelid drooping (ptosis), blurry or double vision (diplopia),unstable gait, a change in facial expression, difficulty in swallowing, shortness of breath, impaired speech, and weakness in the arms, hands, fingers, legs, and neck. Muscle weakness caused by myasthenia gravis worsens as the affected muscle is used repeatedly. Since symptoms typically improve with rest, muscle weakness may come and go. However, the symptoms of myasthenia gravis tend to progress over time, usually reaching their worst within a few years after the onset of the disease.
