Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get StartedSymptoms
By Mayo Clinic staffMuscle weakness caused by myasthenia gravis worsens as the affected muscle is used repeatedly. Since symptoms typically improve with rest, your muscle weakness may come and go. While myasthenia gravis can affect any of the muscles that you control voluntarily, certain muscle groups are more commonly affected than others.
Eye muscles
In more than half the people who develop myasthenia gravis, their first signs and symptoms involve eye problems, such as:
- Drooping of one or both eyelids (ptosis)
- Double vision (diplopia), which may be horizontal or vertical
- Blurred vision, which may come and go
Face and throat muscles
In about 15 percent of people with myasthenia gravis, the first symptoms involve face and throat muscles, which can cause difficulties with:
- Speaking. Your speech may be very soft or sound nasal, depending upon which muscles have been affected.
- Swallowing. You may choke very easily, which makes it difficult to eat, drink or take pills. In some cases, liquids you're trying to swallow may come out your nose.
- Chewing. The muscles used for chewing may wear out halfway through a meal, particularly if you've been eating something hard to chew, such as steak.
- Facial expressions. Family members may note that you've "lost your smile" if the muscles that control your facial expressions are affected.
Arm and leg muscles
Myasthenia gravis can cause weakness in your arms and legs, but this usually happens in conjunction with muscle weakness in other parts of your body — such as your eyes, face or throat. The disorder usually affects arms more often than legs. However, if it affects your legs, you may waddle when you walk.
When to see a doctor
Talk to your doctor if you have trouble:
- Breathing
- Seeing
- Swallowing
- Chewing
- Walking