Symptoms of Generalized Myasthenia Gravis
Reviewed by: HU Medical Review Board | Last reviewed: May 2021
Myasthenia gravis (MG) comes in 2 main types, generalized and ocular. Generalized MG is the most common type, accounting for 85 percent of people with MG. Generalized MG is generally more serious than ocular MG since it causes weakness in many muscle groups.
Muscle weakness
Muscle weakness is the hallmark of myasthenia gravis. With generalized MG, this weakness tends to begin in the eye and gradually spread to other muscle groups. The muscles in the face, neck, and arms or legs are the areas most often affected next.
Weakness in these muscles causes a variety of visible symptoms, such as:1-5
- Droopy eyelids
- Double vision or blurred vision
- Problems speaking, slurred speech
- Expressionless face or trouble smiling
- A lop-sided snarl or sad, downward-turned mouth
- Trouble chewing and swallowing, choking
- Drooling, twitching of the lips
- Nasal tone of voice
- Trouble puckering the lips or whistling
- Difficulty holding the head up or keeping the mouth closed
- Problems brushing hair or climbing stairs
Weakness gets worse as the muscle is used and better after the muscle is rested. Eye symptoms, in particular, tend to happen on one side of the face but can occur on both. The weakness may be better in the morning after the muscles have rested all night and become worse later in the day. Muscle weakness in MG can be very different from day to day or year to year.
Even though most people’s first signs of myasthenia gravis start in the eyes, within 2 to 3 years the weakness spreads to other muscle groups in most people. In the early stages, MG symptoms may disappear for hours, days, or even weeks before coming back.1,2,5
Other symptoms
Generalized MG can cause a variety of other symptoms related to muscle weakness including:3,4
Antibodies and generalized MG
Eight out of 10 people with generalized MG test positive for acetylcholine receptor (AChR) antibodies. Antibodies are chemicals the body makes to attack germs and cancer cells. With an autoimmune condition like MG, the body makes antibodies that attack healthy tissue by mistake. This affects how the muscles work.2
Less common MG antibodies are muscle-specific kinase (MUSK) and lipoprotein- related protein 4 (LRP4). Only 5 out of every 100 people with MG will be seronegative, meaning doctors cannot find any MG antibodies in their blood.2
Different types of MG antibodies cause weakness in different areas of the body.2
Treatment
An acetylcholinesterase inhibitor may be the only drug needed to control mild to moderate generalized myasthenia gravis. Steroids or another immune system drugs may be added if symptoms are not controlled or flares become frequent or serious.1,2,5
Since MG can change over time, sometimes more or less treatment may be needed. Sometimes people need higher doses of steroids or another immunosuppressant drug to bring their disease under control during a flare or when first diagnosed. As symptoms get better they can gradually reduce the amount of steroids needed.1,2,5
Thymectomy is a surgery to remove the thymus gland. It is recommended for people with thymoma, a tumor on the thymus gland. In people with early-onset MG and children with MG, thymectomy often leads to milder symptoms and sometimes even remission. However, it is not usually recommended for people with seronegative, MuSK, or LRP4 myasthenia gravis. Thymectomy is sometimes recommended for ocular MG.1
Other things to know
One out of every 10 people with generalized MG will develop weakness in the muscles that control breathing. If the breathing muscles become very weak, it is called a myasthenic crisis.1
Fewer than 5 out of 100 patients have muscle weakness that begins in the arms and legs where those limbs attach to the trunk. The arms tend to be affected more than the legs.5
If someone’s myasthenia gravis does not respond well to treatments, it may be called refractory MG. Only 15 percent of people with MG have refractory myasthenia gravis.6
