Myasthenia gravis

10-minute read

If you or someone else is having trouble breathing, call triple zero (000) and ask for an ambulance.

Key facts

Myasthenia gravis is an autoimmune disease, caused by a breakdown in communication between your nerves and muscles.
Symptoms include drooping of one or both of your eyelids, blurred or double vision, difficulty swallowing, speaking and breathing and weakness in your limbs.
Blood tests, imaging scans and nerve conduction tests can help diagnose myasthenia gravis.
There is no cure for myasthenia gravis, but there are treatments that can help manage your symptoms.

What is myasthenia gravis?

Myasthenia gravis is a rare autoimmune disease affecting your neuromuscular system. It causes a breakdown in communication between your nerves and muscles. As a result, the muscles that you voluntarily control become weak. These muscles include:

muscles that control eye and eyelid movements
facial muscles
muscles used for chewing, talking and swallowing
neck and limb muscles
muscles involved in breathing such as the diaphragm and intercostal muscles

Examples of involuntary muscles that are not affected by myasthenia gravis include your heart muscle, muscles in your blood vessels or gut.

Males and females from all ethnic groups can get myasthenia gravis. It is most common in females younger than 40 years and males older than 60 years.

What are the symptoms of myasthenia gravis?

Symptoms of myasthenia gravis include:

drooping of one of both of your eyelids
blurred or double vision
difficulty chewing or swallowing
slurred speech
weakness in your arms and legs — you may become unstable when you walk
chronic (ongoing) muscle fatigue
shortness of breath

Your symptoms can appear suddenly, or may take a few weeks to develop. Your muscle weakness can come and go.

Myasthenia gravis symptoms get worse when you are doing activity. They get better after you rest.

Your symptoms and how severe they are can vary between people.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes myasthenia gravis?

Myasthenia gravis is an autoimmune disease — this is when the body's immune system attacks its own healthy cells. In myasthenia gravis, this affect the signals that your nerves send to your muscles. As a result, your muscles cannot work properly.

You are more likely to develop myasthenia gravis if you have a family member with the condition, of if you have other autoimmune diseases or a problem with your thymus gland.

A combination of other factors may trigger myasthenia gravis, including:

an infection
other illness
extreme stress.

If you are pregnant, and have myasthenia gravis, your baby has a higher chance of having a condition known as neonatal (newborn) myasthenia. Neonatal myasthenia is a temporary condition of general weakness in a baby that usually occurs within the first 1 to 2 days after birth and may last days or weeks, but occasionally lasts longer.

A less common type of myasthenia gravis is congenital myasthenia. This inherited problem makes muscle signals weak, and is not an autoimmune issue. People are born with it, but symptoms might not appear until adulthood.

When should I see my doctor?

You should see your doctor if:

you have symptoms of myasthenia gravis and have not been diagnosed
you have a diagnosis of myasthenia gravis and your symptoms are getting worse

Read about how to get the most out of your doctor's appointment.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is myasthenia gravis diagnosed?

Your doctor can diagnose myasthenia gravis by examining you, asking you about your symptoms and referring you to do some of the following tests:

Blood test to check if you have antibodies that are common in people with myasthenia gravis (known as AChR antibodies).
Ice test — your doctor covers your affected eye for a minute or two with a cold pack, and checks for an improvement in eyelid droop.
Nerve conduction tests and electromyography — a test that measures your muscle function.
Tensilon test — an injection of a medicine called edrophonium to check its effect on muscle strength.
Imaging — chest x-ray, CT scan or MRI, to look for problems with your thymus gland

The process of a myasthenia gravis diagnosis can be long and frustrating. Many symptoms are be very general and similar to those of other illnesses. There is no single test that diagnoses myasthenia gravis, you may need to do many tests.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is myasthenia gravis treated?

There is no cure for myasthenia gravis, but treatment can help manage your symptoms.

Treatment for myasthenia gravis can include all or some of the following:

medicines to improve your muscle strength or help balance your immune system
surgery to remove your thymus gland, which is where your body produces the antibodies that attack your muscles
a procedure called ‘plasmapheresis' that temporarily washes out abnormal antibodies from your blood and gives you normal antibodies from donated blood

You will be treated by a neurologist (a nerve specialist). Together, you can consider your medical history, symptoms and age to make the best treatment plan for you. This way you can make an informed decision.

Your doctor may also recommend therapies from allied health professionals to help you cope with your symptoms and improve your quality of life. This can include speech therapists, physiotherapists and dietitians.

Treatment can often improve your muscle weakness, so its best to follow your neurologist's advice. Sometimes, it can help with symptom remission (where your muscle weakness improves and your doctor advises you stop taking your medicines for a while).

Living with myasthenia gravis

If you have myasthenia gravis, try to lead a healthy and active lifestyle. Doctors recommend you look after yourself and to avoid possible triggers.

Triggers can include emotional stress, fever, exerting (‘pushing yourself') too hard, some medicines and illness.

You may find it helpful to join a support group. You could meet people who are going through similar challenges, and get tips from them.

You can wear medical alert jewellery such as a bracelet or necklace. It is a good idea to have a medicine card on you to alert others you have myasthenia gravis in case of emergency. It should include details such as your:

name
date of birth
your doctor
other medical conditions
contact person in an emergency

Usually, having myasthenia gravis doesn't shorten your life. Treatment can also give you a good quality of life.

Exercising with myasthenia gravis

As your doctor to guide you on exercising, so that you continue to move within your limits. Do not exercise if you are weak. You may find it easier to exercise for short amounts of time with breaks, rather than longer sessions.

You may find it useful to keep a diary to note how your body responds to different activities and what kind of rest helps. This way, you can learn how to best use your energy.

It is important you discuss with your healthcare professional which exercise or movement is appropriate for you. Ask your doctor if a referral to an exercise physiologist would help.

Taking new medicines

Before you take a new medicine check with your doctor to see if it is safe to take with myasthenia gravis. This includes:

medicines another doctor prescribes
over-the-counter medicines
complementary medicines
traditional remedies, such as Chinese traditional medicines

What are the complications of myasthenia gravis?

If you or someone else is having trouble breathing, call triple zero (000) and ask for an ambulance.

Myasthenia gravis can cause some complications to your physical and mental health:

Myasthenic crisis

If you have myasthenia gravis, you can experience a myasthenic crisis. This can be a life-threatening medical emergency.

A myasthenic crisis is when the muscles that control your breathing become weak. You may have shortness of breath (be unable to breathe properly). If your condition becomes severe, you may need a ventilator (a life support machine that breathes for you).

An infection, fever, emotional stress or a reaction to a medicine can trigger this crisis.

Swallowing difficulties

If you have swallowing difficulties, you can choke or food and drink can go into your lungs. This is called aspiration. Aspiration can sometimes cause pneumonia (lung infection).

Your doctor can refer you to a speech therapist to help with swallowing and work with you to prevent complications.