Myasthenia Gravis

Medically Reviewed by Brunilda Nazario, MD on March 30, 2023
8 min read

It’s a lifelong autoimmune neuromuscular disease. It causes certain muscles to weaken easily after you use them. Muscle fatigue typically varies throughout the day (sometimes hour by hour) and gets better with rest. 

Myasthenia gravis (MG) disrupts signals between your nerves and voluntary muscles, especially the ones that control your: 

  • Eyes or eyelids
  • Face, jaw, and mouth
  • Neck and throat area
  • Arms, hands, and legs
  • Breathing 

Anyone can get myasthenia gravis (MG), including children. But doctors diagnose the disease most often in women younger than 40 and men older than 60. 

Rarely, babies born to a female parent with MG may have a short-lived version of the disease. This condition is called neonatal myasthenia. Symptoms usually clear up within the first 2 to 3 months of life. 

When you have myasthenia gravis, your immune system attacks the neuromuscular junction. That’s where nerve cells and muscle fibers meet. Everyone with MG has antibodies that block or damage acetylcholine receptors at the neuromuscular junction. 

Acetylcholine is a chemical messenger that tells your muscles to contract. But myasthenia gravis stops or slows this signal way down. And the more you move your muscles, the less acetylcholine you have and the weaker you get. 

Some people with MG have antibodies to other proteins, including muscle-specific kinase and lipoprotein-related protein 4. This also disrupts communication between your nerves and muscles.

It’s not clear why people with myasthenia gravis make these antibodies. Genes likely play a role. And some folks with myasthenia gravis have an enlarged thymus, which researchers think may tell the body to make strength-sapping antibodies. 

Most people who get myasthenia gravis have no family history of the disease. But at least 5% of folks with MG may have another family member with MG or another autoimmune condition. 

Your symptoms may start suddenly and worsen over the course of a few years. But myasthenia gravis affects everyone in a different way. How you feel depends on where you are in your disease course and if you’re on a treatment that works well.

Around 15% to 20% of folks with myasthenia gravis may have a sudden weakness in their jaw, throat, or breathing muscles. This is called myasthenia crisis. Call 911 if this happens to you.

In general, MG may cause symptoms in the following areas: 

Eye muscles. Around half of people with myasthenia gravis start off with visual symptoms. The most common eye symptoms of myasthenia gravis are: 

  • Droopy eyelids (ptosis) 
  • Double vision (diplopia)

Around 15% of people with MG may only have problems with their eye muscles. This is called ocular myasthenia. But most people develop weakness in other muscles later on. 

Face, mouth, and throat. Myasthenia gravis may trigger: 

  • Slurred speech
  • A weak or hoarse-sounding voice
  • Trouble chewing or swallowing
  • A change in your facial expressions

Neck, arms, and legs. You may have trouble:

  • Holding your head up 
  • Using your arms or hands
  • Walking

Breathing muscles. You may be short of breath. Tell your doctor right away if this happens to you. Myasthenia gravis can cause respiratory failure when the muscles that help you breathe get too weak.

While your regular or primary doctor or an ophthalmologist may be able to spot signs of myasthenia gravis, a neurologist will be more familiar with the ins and outs of the disease. This is a doctor trained to diagnose and treat diseases of the brain and nervous system.

The doctor will ask about your symptoms and check your physical health. They’ll also measure your muscle strength, coordination, eye movements, and how well you sense touch. This is called a neurological exam.

If they suspect you have myasthenia gravis, you may need follow-up tests such as:

Blood tests. These check for antibodies (such as acetylcholine receptors or muscle specific kinase) that attack your muscles. Your doctor may also check for signs of other health problems that can mimic myasthenia gravis, such as thyroid disorders. 

Edrophonium test. Your doctor may give you a shot of a medicine to temporarily block the breakdown of acetylcholine in your weak muscles. If you have myasthenia gravis, this test may restore your strength for a short time. 

Electrical nerve stimulation. Your doctor can put a needle into your muscle to detect nerve problems. One way to do this is with an electromyography. This test can show how fast your muscle weakens with repeated use. 

Ice pack or rest test. Your doctor may place an ice pack on your eyes for a couple of minutes to see if that helps lift droopy eyelids. They may also ask you to tire out your eye muscles and then rest to see if your vision gets better. 

Imaging. After you’re diagnosed with myasthenia gravis, your doctor may take a closer look at your thymus gland with a CT scan or MRI. These detailed pictures can show if you have a thymoma – a tumor in the thymus gland. 

Pulmonary function test. This checks how well your lungs work. It’s something you may get if muscle weakness affects your breathing and your doctor thinks you might need a machine to help you breathe (ventilator). 

Write down everything you’d like to know about myasthenia gravis ahead of time. Here are some questions to get you started: 

  • How is MG treated?
  • What makes MG better or worse?
  • Are there certain medications I should avoid?
  • What lifestyle changes should I make?
  • Can I keep working if I have MG?

You may also want to ask: 

  • What kind of exercise is best for someone with MG?
  • Can I get pregnant with MG?
  • What resources can help me learn more about MG?
  • How can I manage MG along with my other health conditions?
  • Are there assistance programs to help me pay for treatment?
  • Can I join a clinical trial?

Here are some questions your doctor may ask you: 

  • Are your symptoms worse in the morning or afternoon?
  • How much does muscle weakness affect your daily life?
  • Does anything help or worsen your symptoms?
  • Which symptoms bother you most?
  • What are your treatment goals?

Your doctor’s approach to treatment depends on several things, including how serious your symptoms are and if your disease is quickly getting worse. In general, treatment for myasthenia gravis may include: 

Drugs to increase muscle strength. If you have mild to moderate myasthenia gravis, the first thing you doctor may give you is a drug to boost acetylcholine in your muscles. Common choices include anticholinesterase drugs such as pyridostigmine (Mestinon).

These drugs can increase strength within 15 to 30 minutes for some people. The effects typically last for 3 to 4 hours or longer. Cholinesterase inhibitors may be the only treatment some people need, but they don’t work for everyone or every muscle. 

Drugs to suppress your immune system. Most people with myasthenia gravis need medication that slows down the immune system. At first, you may get strong steroids like prednisone. After your symptoms improve, your doctor may transition you to nonsteroidal immunotherapy. 

Long-term immunosuppressive drugs may take several months to work. Some that are commonly used to treat myasthenia gravis are: 

  • Azathioprine
  • Mycophenolate mofetil
  • Tacrolimus
  • Cyclosporine 

Thymectomy. Your doctor may take out your thymus gland. This surgery may ease symptoms of myasthenia gravis whether you have a tumor on your thymus or not. But you may not know if you’ll feel better for several years. 

Intravenous (IV) therapy. You may need special treatment through a vein in your neck, chest, or arm if your symptoms get worse fast (myasthenia crisis), other drugs don’t ease your symptoms enough, or you’re going to get surgery to remove your thymus later. 

IV therapy for myasthenia gravis includes: 

  • Plasmapheresis. Also called plasma exchange, this procedure removes harmful antibodies from your blood and replaces it with healthy plasma or a plasma substitute.
  • Intravenous immunoglobulin (IVIG). Your doctor may give you antibodies from donor blood. This can change the way your immune system works for a short time.
  • Monoclonal antibodies. These are manmade antibodies that target certain parts of your overactive immune system. 

You didn’t cause your disease, but healthy lifestyle changes may help you feel better. Along with medical treatment, you’ll want to: 

Get good nutrition. If weakness makes it hard to follow a healthy diet, you may need to eat small meals throughout the day or chow down when your energy is highest. You can also ask your doctor about taking MG medication to boost your strength before you eat. 

Find the right way to exercise. Your muscles may fatigue easily, but regular movement may boost your energy in the long run. Still, it’s important to exercise within your limits. Work with your doctor or a physical therapist to find a workout routine that’s safe for you. 

Rest when you’re tired. You can continue to live an active lifestyle, including going to the gym or running errands. But don't push past the early signs of fatigue. Ask your doctor how to know when you need to take breaks. 

Know your triggers. You may get more weakness when you’re sick, very active, on your period, or after you’ve had a baby. Certain medications and supplements may also worsen MG symptoms. Work with your doctor to know what to watch for.

It’s common for people with myasthenia gravis to also have mental health conditions, such as anxiety and depression. People whose weakness leads to life-threatening breathing episodes may have a higher chance of posttraumatic stress disorder (PTSD).

Ask your doctor to refer you to a psychologist or therapist who works with people who have MG or similar conditions. They’ll help you learn how to manage life with an ongoing illness. 

Symptoms tend to peak within the first few years and may become easier to manage over time. But keep in mind that myasthenia gravis is a mostly treatable disease. Work with your doctor to find lifestyle changes and medication that work best for you. 

And while there's no cure, most people with MG can live a full life. You may even have long periods with little to no symptoms. But there’s no way to know when or how long you’ll be in remission.

You may not know anyone else who has myasthenia gravis. But you’re far from alone. Ask your doctor or a social worker if there’s an online or in-person support group your area. Connect with the larger MG community through websites and groups such as: 

  • Myasthenia Gravis Foundation of America
  • Myasthenia Gravis Rare Disease Network
  • Myasthenia Gravis Hope Foundation
  • Conquer Myasthenia Gravis 

To find more information and resources about myasthenia gravis and similar conditions, visit the Autoimmune Association and Muscular Dystrophy Association. 

Your support can go a long way to help your loved one manage life with myasthenia gravis. Here are some key things to keep in mind if you care for someone with MG: 

Learn as much as you can. The ups and downs of myasthenia gravis can be hard to grasp if you don’t live with the disease. Respected groups like the Myasthenia Gravis Foundation of America offer instructional brochures and videos that may help you better understand the changing nature of MG. 

Ask how you can help. Not everyone with myasthenia gravis needs or wants the same kind of support. Talk to your loved one about their specific needs. 

Connect with other caregivers. Many online or in-person support groups are open to friends and family members of people with myasthenia gravis. Ask your doctor, search social media, or visit the Myasthenia Gravis Foundation to find support near you. 

Take care of yourself. It’s natural to want to do as much as you can on your own, but it’s important to ask for help when you need it. Reach out to friends and family for help with everyday things. Talk to your doctor about professional mental health care when there’s too much stress to handle on your own.