Symptoms of Myasthenia Gravis

In This Article

Myasthenia gravis (MG) is a neuromuscular disorder that causes gradual progressive weakness of the skeletal muscles—the muscles that allow the body to move. “Myasthenia gravis” literally means “grave muscle weakness.”

According to the Myasthenia Gravis Foundation of America, the prevalence of MG is around 36,000 to 60,000 in the United States. The condition can affect anyone any age, but it is more common in women younger than age 40 and men over age 60.

There is no cure for MG, but thanks to currently available treatment options, most cases of MG are not as grave the name seems to suggest. Treatment can help to manage symptoms, including muscle weakness of the limbs and eyes, problems with speaking, chewing, swallowing, and breathing, and debilitating fatigue.

Most people with MG can enjoy a good quality life even with mild to moderate symptoms and have a normal life expectancy.

Muscle Weakness
 seksan Mongkhonkhamsao/Getty Images

Frequent Symptoms

MG is an autoimmune disease where abnormal immune system responses cause autoantibodies to block or destroy certain muscle and nerve receptors. The result is interrupted communication at the neuromuscular junction—the area where nerve nerves connect to muscles they would control. When this happens, nerve impulses are prevented from triggering muscle contractions.

For most people, the onset of MG is gradual and often, signs and symptoms are not immediately noticed. The severity of symptoms will vary from person to person.

MG can affect any of the voluntary muscles, but it tends to affect specific muscle groups. The muscle groups most frequently affected are the eye muscles, the face and throat muscles, and the arm and leg muscles. 

Muscle Weakness

The main symptom of MG is the weakness of the voluntary skeletal muscles. The skeletal muscles are attached to the bones by tendons, and they produce all the movements of your body. These muscles are under your control, as you are able to move them.

Weakness associated with MG will get worse with activity and improve with rest. The degree of muscle weakness will vary for each individual affected. It can range from a mild form where only a few muscles are affected to a severe form that affects many muscles. 

MG may cause the skeletal muscles to get weaker with time, especially if the condition is not treated or undertreated.

Eye Muscle Problems

More than 50% of people with MG will have eye problems. Eye symptoms result because the muscles controlling eye and eyelid movement are affected by the condition.

Eye symptoms of MG include:

  • Ptosis: Drooping of one or two eyelids
  • Diplopia: Double vision, which can be vertical or horizontal and improves when one eye is closed
  • Ophthalmoparesis: A partial paralysis of eye movements

Eye symptoms range from mild to severe. They can change from day to day and throughout the day. Eye problems tend to be worse at the end of the day and can improve for short periods by resting the eyes.

For many people with MG, eye problems are usually the first symptoms experienced with MG.

Face and Throat Muscle Weakness

Myasthenia gravis can cause symptoms in the face and throat muscles.

Symptoms related to the face and throat muscles involve:

  • Dysarthria: MG can impair speech and cause the voice to sound hoarse, nasally, weak, or soft, depending on which face and throat muscles have been affected.
  • Dysphagia: MG will cause problems with eating, drinking, and/or taking medication. It affects swallowing and causes a person with the condition to choke more easily. For some people, trying to swallow liquids can cause fluid to come out of the nose.
  • Problems with chewing: This happens because the muscles used for chewing give out halfway through a meal or with eating something is hard to chew, like steak.
  • Changes to facial expressions: Changes to facial expressions occur when the muscles that control facial expressions are affected. A snarling (vertical-looking) smile or sullen facial expression can be caused by facial weakness.
  • Muscle atrophy: While rare, some people with MG will develop muscle atrophy in their face and tongue muscles which can make face and throat symptoms much worse. Muscle atrophy is when muscles start to waste away. 

Weakness of Other Body Parts

Muscle weakness in MG can eventually spread to the neck, arms, hands, legs, and feet. Once this happens, a person with the condition may not be able to lift their arms over their head. They are not able to perform physical tasks, including walking long distances, climbing steps, getting up from a sitting position, and gripping heavy objects.

Constant tiredness and aching muscles after physical activity are also common with MG. Achiness and tiredness are usually worse in the upper part of the body than in the legs and feet.

Debilitating Fatigue

Fatigue is believed to be one of the most debilitating symptoms of MG. A study reported in 2016 by the journal Brain and Behavior finds the prevalence of fatigue in the MG study group was 56.1%. Researchers concluded this fatigue negatively affected the ability to complete activities of daily life and have a good quality of life.

Together with muscle weakness, fatigue can severely affect your life enjoyment. It can make you too tired to participate in your favorite activities, to spend time with loved ones, and to be productive at home and on the job. It will cause you to feel sleepy even after sleeping a full night’s sleep.

Treatments for MG can be helpful in improving fatigue levels for some people. But for others, life with MG fatigue can be challenging and negatively affect quality of life.

Rare Symptoms

When MG affects the muscles that control breathing, a myasthenic crisis can occur. A myasthenic crisis is a disease complication caused by the worsening of muscle weakness leading to respiratory failure.

MG can involve the diaphragm and the chest muscles that help with breathing. A myasthenic crisis can cause breathing to be fast and shallow or ineffective. The airway can also become blocked from secretion buildup and weakness of throat muscles.

Myasthenic crisis affects up to 20% of people with newly diagnosed MG. It is also common in people who are untreated, who are slow to respond to treatment, and who have rapid disease progression.

Certain triggers can make MG symptoms worse and may lead to a myasthenic crisis. Such triggers include stress, lack of sleep, sickness, overexertion, pain, extreme weather temperatures (hot or cold), hot showers or baths, some foods and beverages, and chemical exposure, such as with lawn treatments or insecticides.

Some commonly used medications like calcium channel blockers, lithium, verapamil, and some antibiotics have been known for making MG symptoms worse.

A myasthenic crisis is treated with mechanical ventilation and intubation. Mechanical ventilation uses a breathing machine called a ventilator to move air in and out of the lungs. In order to connect the lungs to ventilator, a doctor inserts a narrow tube into the mouth to the windpipe in a process called intubation.

In a severe myasthenic crisis, a person will be on a ventilator until their muscle strength returns.

Complications/Sub-Group Indications

As with other autoimmune disorders, people will MG will go on to develop additional conditions. Further, MG seems to affect females much more severely than males.

Comorbidities

Research shows up to 90% of people diagnosed with MG will go on to develop comorbidities of the condition, according to a study reported by the journal Acta Neurologica Belgica.

The term “comorbidity” is used when referring to the presence of more than one medical condition affecting the same person. Females with early onset of the disease have the highest incidence of comorbidities, including other autoimmune diseases.

Comorbid conditions associated with MG include dyslipidemia (abnormal amount of lipids in the blood), thyroid disease, diabetes, hypertension, and autoimmune diseases, like rheumatoid arthritis and autoimmune thyroid disorder. Comorbid conditions can contribute to poor treatment response and decreased quality of life.

Disease Severity

MG is a condition that affects both males and females and it occurs across all ethnic and racial groups. The age of onset varies between the genders. Early disease onset MG (earlier ages) is more prevalent in females while late onset is more common in males. Disease severity may be also affected by gender.

In an observational, cross-sectional population study reported in 2016 in the journal PLoS One, researchers aimed to quantify muscle weakness in MG. They wanted to determine if gender, treatment intensity, and disease duration affected muscle strength and disease progression. Researchers determined muscle weakness was more evident in the female study participants.

In addition to affecting females at earlier ages, early onset MG has been associated with higher rates for hyperplasia (enlargement of the thymus gland) and higher levels of acetylcholine receptor (anti-AChR) autoantibodies, which means more severe disease symptoms.

The thymus gland lies in the chest area and it plays an important role in forming the body’s immune system during childhood. This gland gets smaller and is replaced by fatty tissue as we age. It can be abnormal and large in some people with MG.

Anti-AChRs proteins are located in skeletal muscle fibers. In MG, they are the target of auto-antibodies responsible for causing the disease and keeping it active.

When To See a Doctor/Go To the Hospital

You should see a doctor if you experience sudden-onset weakness, fatigue, or pain and don’t know the cause of these symptoms. You should contact your doctor if you find you are feeling well one minute, and then suddenly you feel severe exhaustion, pain, and/or other severe symptoms you have never before experienced. 

Temporary muscle soreness from physical activity is normal. But muscle pain with no known cause that lasts for two or more weeks should be checked out by a doctor. Muscle weakness of the arms, hands, fingers, or neck and fatigue lasting more than two weeks should also be checked out, as this is probably a sign something wrong.

You should see your doctor if you experience any of the eye symptoms associated with MG, including blurry or double vision, droopy eyelids, or tired eyes. Mouth or jaw weakness affecting chewing, swallowing, or facial expressions, or causing slurred speech should also be checked out.

When To Go To the Hospital

Sudden weakness in certain parts of the body might indicate a more serious problem. For example, if you are experiencing severe muscle weakness or numbness on one side of the body or in the face, you should go to the emergency room.

While some of these symptoms are seen in MG, if these are new symptoms or are severe, they may indicate a stroke. Other stroke symptoms include confusion, slurred speech, face drooping, and weakness in the legs.

You should go to an emergency if you have weakness in your entire body that is accompanied by fever, low blood pressure, fainting, dizziness, or a racing heartbeat. 

A myasthenic crisis may require you to go to the hospital. If symptoms do not appear life-threatening, reach out to your doctor for advice. However, if you cannot get hold of your doctor, if you find you are having severe breathing and swallowing difficulties, or your weakness worsens quickly, get to an emergency room right away or call 911.

A Word From Verywell

Most people with MG live a life with few flare-ups provided they stick with their treatment plans. The condition can spread across the body and some people experience significant symptoms and severe disease activity. While death from complications of MG is possible, most people with the condition will not see a change in life expectancy.

Symptoms of myasthenia gravis can improve with treatment. The goal of treatment is to improve muscle function and prevent any swallowing or breathing problems. With effective treatment, most people will experience muscle strength improvement and will lead normal lives.

Of course, not everyone with MG will respond well to treatment or see immediate symptom improvement. Some may need therapy for swallowing and breathing. You should work with your doctor to come up with an appropriate and successful treatment plan to improve disease symptoms and quality of life.

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