Myasthenia gravis

A breakdown in the communication between nerves and muscles causes weakness and fatigue of muscles under your control.

Update Date: 22.08.2025

Overview
Symptoms
Causes
Symptoms
Causes
Risk factors
Complications
Diagnosis
Treatment
Lifestyle and home remedies
Coping and support
Preparing for an appointment

Overview

Myasthenia gravis is a condition that happens when communication between nerves and muscles breaks down. This causes muscles to feel weak and get tired quickly. This condition may affect any of the muscles you control, called voluntary muscles. Certain muscle groups are more commonly affected than others. These include muscles in the face, throat, arms and legs.

Your eyelids may droop, you may have double vision, trouble speaking or eating, or you may have trouble holding up your head because of weak neck muscles. Myasthenia gravis can happen at any age. But it's more common in people younger than 40 who were assigned female at birth and people older than 60 who were assigned male at birth.

There's no way to prevent or cure myasthenia gravis. But treatment can help manage symptoms.

Symptoms

Symptoms of myasthenia gravis may come and go. They usually get better when the weak muscle is rested but get worse again when the muscle is used. Symptoms often progress and may be at their worst one or two years after the disease begins.

Common symptoms of muscle weakness with myasthenia gravis include:

Eye muscles

In more than half of people with myasthenia gravis, the first symptoms involve eye muscles, such as:

  • Drooping of one or both eyelids, called ptosis.
  • Double vision, called diplopia. This may affect the horizontal or vertical vision. It may improve or stop when one eye is closed.

Face and throat muscles

In about 15% of people with myasthenia gravis, the first symptoms involve face and throat muscles. It may be hard to:

  • Speak. Your speech might sound soft or nasal, depending on which muscles are affected.
  • Swallow. You may choke easily, making it difficult to eat, drink or take pills. At times, when you swallow liquid, it may come out of your nose.
  • Chew. The muscles used for chewing might tire halfway through a meal. This is especially true if you've been eating something hard to chew, such as steak.
  • Control facial expressions. For example, you might have trouble fully raising your eyebrows or holding a smile because the muscles tire quickly. Your facial expression may not fully reflect what you are feeling.

Neck and limb muscles

Myasthenia gravis also may cause weakness in the neck, arms and legs. These symptoms may happen later as the condition worsens. Weakness in the legs can affect how you walk. Weak neck muscles can make it hard to hold up the head.

When to see a doctor

Talk with your healthcare professional if you have trouble with any of the following:

  • Breathing.
  • Vision.
  • Swallowing.
  • Chewing.
  • Walking.
  • Using your arms or hands.
  • Holding up your head.

Causes

The exact cause of myasthenia gravis is not known. Myasthenia gravis is an autoimmune condition. These conditions happen when the immune system creates antibodies that mistakenly work against or attack healthy cells or tissue. Antibodies are proteins that help fight unhealthy or foreign substances in the body, such as bacteria or viruses.

Antibodies

In myasthenia gravis, the immune system mistakenly makes antibodies that stop the neurotransmitter acetylcholine from communicating with muscles.

Nerves communicate with muscles by releasing chemicals called neurotransmitters that send signals between cells.

The antibodies destroy or block the path to muscle cells called receptor sites. With fewer receptor sites available, the muscles receive fewer nerve signals. This causes muscle weakness.

Myasthenia gravis also may happen if antibodies block proteins such as muscle-specific receptor tyrosine kinase, also called MuSK, or lipoprotein-related protein 4, also called LRP4. These proteins work together to form strong connections between nerve cell signals and muscles. When antibodies block MuSK or LRP4, the signal between nerves and muscles is limited or does not get through, leading to muscle weakness. Research likely will continue to find other antibodies that play a role in myasthenia gravis.

Myasthenia gravis is not always caused by antibodies that block acetylcholine, MuSK or LRP4. A type of myasthenia gravis called seronegative myasthenia gravis is known as antibody-negative myasthenia gravis. In general, researchers believe this type of myasthenia gravis still happens because of issues with the immune system, but the antibodies involved are not yet known.

Receptors

Chemical messengers called neurotransmitters fit precisely into receptor sites on muscle cells. In myasthenia gravis, certain receptor sites are blocked or destroyed, causing muscle weakness.

Symptoms

Thymus gland

Researchers believe the thymus gland makes or helps make the antibodies that block acetylcholine. The thymus gland is part of the immune system. It is located in the upper chest beneath the breastbone.

The thymus gland is large in babies and small in adults who don't have health conditions. In some adults with myasthenia gravis, the thymus gland is larger than usual. Some people with myasthenia gravis also have tumors of the thymus gland. These tumors are called thymomas. Thymomas are cancer, but they usually aren't malignant. This means the cancer typically does not spread throughout the body. These tumors may be removed with surgery.

Thymus gland

The thymus gland, a part of the immune system, is in the upper chest beneath the breastbone. The thymus may trigger or support the production of antibodies that result in muscle weakness.

Causes

Other causes

Children born to people with myasthenia gravis may rarely have the condition at birth. This is called neonatal myasthenia gravis. If treated immediately, children usually recover within two months after birth.

Some children are born with a rare hereditary form of myasthenia gravis called congenital myasthenic syndrome. Congenital myasthenic syndrome is often treated with medicine to manage symptoms.

Factors that can make myasthenia gravis worse include:

  • Fatigue.
  • Illness or infection.
  • Surgery.
  • Stress.
  • Some medicines:
    • Beta blockers.
    • Quinidine gluconate, quinine sulfate (such as Qualaquin).
    • Phenytoin (such as Dilantin).
    • Some anesthetics and antibiotics.
  • Pregnancy.
  • Menstrual periods.

Risk factors

While the exact cause of myasthenia gravis is not fully understood, certain factors may increase the likelihood of having it.

  • Genetics. A personal or family history of autoimmune conditions may put you at higher risk.
  • Thymus gland issues. Having an enlarged thymus or a thymoma may play a role in myasthenia gravis.
  • Age and sex assigned at birth. Myasthenia gravis is more common in people younger than 40 who were assigned female at birth, and in people older than 60 who were assigned male at birth.
  • Lifestyle and health. Stress, infections and some medicines may trigger the condition in some people.

These factors increase the risk but do not mean you will get myasthenia gravis.

Complications

Complications of myasthenia gravis are treatable, but some can be life-threatening.

Myasthenic crisis

Myasthenic crisis is a life-threatening condition. It happens when the muscles that control breathing become too weak to work. Emergency treatment and mechanical assistance with breathing are needed. Medicines and therapies that filter the blood help people breathe on their own.

Thymus gland tumors

Some people with myasthenia gravis have tumors in their thymus glands. The thymus gland lies under the breastbone and is part of the immune system. Most of these tumors, called thymomas, are not malignant, meaning they likely will not spread and can be removed with surgery.

Other conditions

People with myasthenia gravis often have other autoimmune conditions, such as:

  • Thyroid disease. The thyroid is a gland located in the neck that helps manage metabolism. Metabolism is how the body uses energy. If your thyroid is too active or not active enough, you may have a hard time managing body temperature and weight and you may have other symptoms.
  • Rheumatoid arthritis. This condition causes inflammation and pain, typically in the bones of joints.
  • Lupus. In this condition, the immune system attacks healthy tissues throughout the body. This can damage the skin, joints, kidneys, heart and brain. Symptoms range from mild, such as fatigue, joint pain and skin rashes, to severe, such as kidney inflammation or cardiovascular issues.

Diagnosis

Your healthcare professional talks to you about your symptoms, reviews your medical history and does a physical exam. Your health professional also does a neurological exam.

Neurological exam

During a neurological exam, your health professional may test:

  • Reflexes.
  • Muscle strength.
  • Muscle tone.
  • Senses of touch and sight.
  • Coordination.
  • Balance.

There are several other tests your care team may use to diagnose myasthenia gravis.

Ice pack test

If you have a droopy eyelid, your health professional might put a bag filled with ice on your eyelid. After two minutes, your health professional removes the bag and checks whether the eyelid is less droopy.

Blood test

A blood test might show antibodies that interrupt the receptor sites where nerves signal your muscles to move.

Repetitive nerve stimulation

In this nerve conduction study, a healthcare professional attaches electrodes to the skin over the muscles to be tested. Small pulses of electricity are sent to the nerve going to that muscle. These pulses measure whether the nerve can send a signal to the muscle.

The nerve is tested several times to see if its ability to send signals gets worse with fatigue. If your nerve tires, this may be a sign of myasthenia gravis.

Single-fiber electromyography, also called EMG

This test measures the electrical activity traveling between your brain and your muscles. It involves inserting a fine wire electrode through your skin and into a muscle to test a single muscle fiber.

Imaging

Your health professional might order a CT scan or an MRI to check for a tumor or other concerns with your thymus.

Pulmonary function tests

These tests measure whether your condition is affecting your breathing.

Treatment

Various treatments, alone or together, can help with symptoms of myasthenia gravis. Your treatment depends on your age, how severe your disease is and how fast it's progressing.

Medicines

  • Cholinesterase inhibitors. Medicines such as pyridostigmine (Mestinon, Regonol) improve communication between nerves and muscles. These medicines aren't a cure but may improve muscle contraction and strength in some people.

    Possible side effects include gastrointestinal upset, diarrhea, nausea, and too much saliva and sweat.

  • Corticosteroids. Corticosteroids such as prednisone block the immune system, making it less able to produce antibodies. But use of corticosteroids over a long period of time can lead to serious side effects. These include bone thinning, weight gain, diabetes and a higher risk of some infections.

  • Immunosuppressants. Your health professional also might prescribe other medicines that change your immune system. These medicines could include azathioprine (Azasan, Imuran), mycophenolate mofetil (Cellcept), cyclosporine (Sandimmune, Gengraf, others), methotrexate (Trexall) or tacrolimus (Astagraf XL, Prograf, others). These medicines, which can take months to work, might be used with corticosteroids.

    Side effects of immunosuppressants, such as a higher risk of infection and liver or kidney damage, can be serious.

Intravenous therapy

The following therapies are usually used for a short time to treat symptoms that suddenly get worse. They also may be used before other therapies or surgery.

  • Plasmapheresis. This procedure uses a blood-filtering machine similar to that used for dialysis. The machine removes antibodies from the blood that block the transmission of signals from nerve endings to your muscles. However, the benefits from this procedure usually last only a few weeks. Having this done several times can make it hard to find veins for further treatments.

Risks of plasmapheresis include a drop in blood pressure, bleeding, heart rhythm conditions and muscle cramps. Some people have an allergic reaction to the solutions used to replace the plasma.

  • Intravenous immunoglobulin. This therapy provides your body with typical antibodies. This alters your immune system response. Benefits are usually seen in less than a week and can last 3 to 6 weeks.

Side effects are usually mild. They may include chills, dizziness, headaches and fluid retention.

  • Rituximab (Rituxan). This is a medicine injected into a vein to treat myasthenia gravis. It works by targeting proteins on B-cells. Other medicines that are similar B-cell-depleting monoclonal antibodies may increase over time. These medicines are usually used when other treatments don't work. They can have serious side effects.

Neonatal Fc receptor blockers

Neonatal Fc receptor blockers stick to and block a protein called the neonatal Fc receptor. This lowers the amount of certain antibodies in the body, including the ones that cause symptoms of myasthenia gravis. Examples include:

  • Efgartigimod (Vyvgart). This medicine is given through an IV or an injection every week for 4 weeks. This is usually done several times.
  • Rozanolixizumab (Rystiggo). This medicine is given through an IV every week for 6 weeks. This is usually done several times.

Other therapies

Molecular therapies target specific molecules in a cell. They work on a part of the immune system called the complement system. Therapies may include:

  • Eculizumab (Soliris) and ravulizumab (Ultomiris). These medicines are given through an IV every 2 to 6 weeks. You must have a meningococcus vaccination or be on antibiotics to prevent meningococcus infection.
  • Zilucoplan (Zilbrysq). This therapy is a daily injection that can be done at home. It blocks a harmful protein and helps stop muscle damage. Newer therapies also target a protein in the cells that breaks down the harmful antibodies more quickly. These newer therapies are called FcRN receptor blockers.
  • Chimeric antigen receptor (CAR) T-cell therapy. This therapy is being studied to treat people with myasthenia gravis who do not respond to standard therapies.

These therapies also may be combined with traditional treatments and other therapies. For some, these may be promising alternatives, but research is ongoing.

Surgery

Some people with myasthenia gravis have tumors in their thymus glands. A thymus gland tumor is called a thymoma. If you have a thymoma, you'll likely need surgery to remove the thymus gland. The surgery is called thymectomy.

Even if you don't have a tumor in the thymus gland, removing the gland might improve your symptoms. However, it may take years to see the benefits of this surgery.

The thymectomy can be done as an open surgery or as a minimally invasive surgery.

During open surgery to remove the thymus, a surgeon splits the breastbone, called the sternum, to open the chest and remove the thymus gland.

During minimally invasive surgery, the surgeon uses video cameras or robot-assisted tools to help guide the surgery. This allows the surgeon to use smaller incisions to remove the thymus.

  • Video-assisted thymectomy. Typically, surgeons make a small opening in the neck or a few small openings in the side of the chest. They then use a long, thin camera, called a video endoscope, and small instruments to see and remove the thymus gland.
  • Robot-assisted thymectomy. Surgeons make several small openings in the side of the chest. They use a robotic system that includes a camera and mechanical arms with attached surgical instruments to remove the thymus gland.

Minimally invasive surgeries may cause less blood loss and less pain than open surgery does. They also may increase survival rates and shorten hospital stays.

Your surgeon decides the type of surgery that is best for you. This may depend on your thymus gland, tumor and overall health.

Lifestyle and home remedies

To help you make the most of your energy and cope with the symptoms of myasthenia gravis:

  • Adjust your eating routine. Try to eat when you have good muscle strength. Take your time chewing your food and take a break between bites. You might find it easier to eat small meals several times a day. Also, try eating mainly soft foods and avoid foods that require more chewing, such as raw fruits or vegetables.
  • Use safety precautions at home. Install grab bars or railings where you need support, such as next to bathtubs or stairs. Keep your floors clean and move area rugs to prevent tripping. Outside your home, keep paths, sidewalks and driveways cleared of leaves, snow and other debris that could cause you to trip.
  • Use electric appliances and power tools. To save your energy, try using an electric toothbrush, electric can openers and other electrical tools to perform tasks.
  • Wear an eye patch. If you have double vision, an eye patch can help. Try wearing one to write, read or watch television. Switch the eye patch to the other eye regularly to help reduce eyestrain.
  • Plan. If you have chores, shopping or errands you have to do, plan the activity for times during the day when you typically have the most energy.

Coping and support

Coping with myasthenia gravis can be hard for you and your loved ones. Stress can make your condition worse, so find ways to relax. Ask for help when you need it.

Learn all you can about your condition, and have your loved ones learn about it as well. Families may benefit from a support group to meet people who understand the challenges of managing myasthenia gravis.

Preparing for an appointment

You'll likely see your primary healthcare professional first. Your health professional may refer you to a doctor trained in nervous system conditions, called a neurologist, for further evaluation.

Here's information to help you get ready for your appointment.

What you can do

Take a friend or family member along to help you understand the information you're given. Make a list of:

  • Your symptoms and when they began.
  • All medicines, vitamins and supplements you take, including doses.
  • Questions to ask your healthcare professional.

For myasthenia gravis, questions to ask your healthcare professional include:

  • What is likely causing my symptoms?
  • What tests do I need?
  • What course of action do you recommend?
  • What are the alternatives to the approach you're suggesting?
  • I have other health conditions. How can I best manage them together?
  • Are there restrictions I need to follow?
  • Are there brochures or other printed materials I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Be prepared to answer questions your healthcare professional is likely to ask, such as:

  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?

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