Weakness and fatigability of muscles are the cardinal symptoms.
This means, painless weakness which increases on muscle use and improves after rest. In most patients weakness begins in eye muscles and result in:
- Drooping eyelids
- Blurred or double-vision
Weakness may affect almost any skeletal muscle as the disease progresses.
Other common symptoms are:
- Slurring of speech
- Difficulty in chewing and swallowing
- Nasal regurgitation
- Weakness in the arms and legs
- Difficulty with breathing in very severe forms of myasthenia gravis. This is termed myasthenia crisis.
Distribution and severity of weakness is variable. An established weakness may increase with anxiety; infection; or with menstrual period. It may improve with rest.