Myasthenia gravis typically does not affect your life expectancy. But some severe complications, such as respiratory failure, can be life threatening, particularly in the early years of the disease.

Myasthenia gravis (MG) is a rare autoimmune and neuromuscular disease that affects the connections between your nerves and muscles. It can cause significant fatigue and weakness of certain voluntary muscle movements throughout your body, often disrupting everyday activities.

Experts estimate that 150–200 per 1 million people worldwide have MG. There may be 30,000–60,000 people living with MG in the United States. However, because the disease is underdiagnosed, the actual number is likely higher.

MG is a progressive disease, so it’s important to recognize how the symptoms may change and progress over your lifetime.

MG can affect the voluntary muscle movements you need for everyday activities. But the disease in itself is not deadly, and most people with MG have a typical life expectancy.

In rare cases, MG may be life threatening. This is usually due to severe MG that affects the respiratory system.

The onset of MG can be sudden. For this reason, a doctor may not suspect MG until the disease has progressed.

Doctors classify MG as either ocular or generalized. Ocular MG involves symptoms that begin in your eyes. It causes weakness in your eye muscles and eyelids, which can lead to vision problems and drooping of your eyelids.

Generalized MG involves symptoms that affect your eyes and other muscles in your body. It may affect your legs and arms, your head, and your respiratory system.

Generalized MG may cause difficulties with:

  • eating
  • swallowing
  • holding up your head
  • speaking
  • walking
  • sitting up
  • climbing stairs
  • gripping and holding objects
  • breathing

Order of progression

MG often affects some body parts before others. This progression can take several weeks to years and often occurs in the following order:

  1. eyes
  2. face
  3. neck
  4. arms and shoulders
  5. hands
  6. legs

Severe MG may also affect your respiratory system.

No matter which areas of your body MG affects, your symptoms are likely to fluctuate. You may experience severe symptoms one day and very few symptoms the next day. This type of fluctuation may even occur within a single day.

How quickly does myasthenia gravis progress?

Overall, MG can become its most severe within 1–3 years. But you may also experience periods of remission, which can last several years at a time.

About 50% of people with MG tend to develop ocular symptoms first. Ocular MG may then develop into generalized MG.

Juvenile onset MG (MG that a doctor diagnoses during childhood) tends to progress much more slowly and to have a higher likelihood of remission.

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With treatment, you can live an active life with MG. Still, it’s important to discuss the possible complications of the disease with a doctor.

Respiratory failure related to MG — also called a myasthenic crisis — is one potential complication. This affects your ability to breathe, and it’s a medical emergency. Seek emergency medical help right away if you or a loved one has MG and is having trouble breathing.

Up to 1 in 5 people with MG will experience a myasthenic crisis in their lives, though it usually occurs within the first 2 years of having the disease.

It’s also important to consider potential complications of MG treatments. Immunosuppressants are particularly notorious for causing side effects, which may include:

As you talk with a doctor about your individual experiences with MG, consider discussing the following common questions.

What is end stage myasthenia gravis?

The term “end stage” often refers to the last stage of a progressive condition. MG does not have a final chronic (long-term) stage before death. However, a myasthenic crisis can be a serious, life threatening complication.

Some people may confuse the term “end stage MG” with “late onset MG,” which refers to MG that begins after age 50 years.

Can you reverse myasthenia gravis?

At this time, there’s no way to reverse MG, and there’s no known cure. However, about 20% of people with MG may experience remission. This involves a temporary reversal of symptoms for several years but not a reversal of the entire condition.

As many as 1 in 5 people with MG also develop a type of tumor called a thymoma. If doctors find and surgically treat a thymoma, MG may go into remission.

What is the death rate for myasthenia gravis?

Research suggests that 5–9% of people with MG die as a result of the disease. The two primary risk factors for death from MG are older age and respiratory failure.

When adjusting for age, about 1.86 per 1 million people die from MG, according to a 2023 Chinese study. Males have almost double the mortality rate of females.

Is myasthenia gravis hereditary?

MG itself is not hereditary. However, as with other autoimmune diseases, some people may have a genetic predisposition to developing MG.

MG is a rare but serious autoimmune disease that can affect your everyday activities and quality of life.

Treatments can help minimize the reactivity in your immune system that contributes to MG. Generally, people with MG have the same life expectancy as people without it.

Due to fluctuating symptoms, MG is likely underdiagnosed. If you suspect that you or a loved one may have MG or if autoimmune diseases run in your family, consider talking with a doctor. The earlier you begin to treat MG, the better the overall outlook will be.