Myasthenia Gravis Symptoms: Early Signs and Crisis Warning Signs

By Anna Curran, RN, BSN, PHN · Last reviewed October 2026

The most common myasthenia gravis symptoms are droopy eyelids, double vision and muscle weakness that gets worse with use and better with rest. Many people also have trouble chewing, swallowing, speaking clearly or lifting their arms. Trouble breathing is the most serious symptom and needs emergency care right away.

MG weakness can be sneaky. It may come and go, so it is easy to brush off at first. Here is what to watch for, from the earliest signs to the warning signs of a crisis.

The Hallmark of MG: Weakness That Tires Out

The key feature of MG is muscle weakness that gets worse the more you use a muscle. It improves after rest. This is sometimes called “fatigable weakness.”

Here is what that can look like in daily life:

You feel fine in the morning but weaker by evening.
Your eyelid droops more after reading or watching TV.
Your jaw gets tired partway through a meal.
Your arms feel heavy after brushing your hair.

This is different from feeling sleepy or worn out. It is the muscle itself that stops working well, then recovers with rest.

Early Signs of Myasthenia Gravis

Eye symptoms (often first)

According to Mayo Clinic, in more than half of people with MG, the first symptoms involve the eye muscles. Watch for:

Droopy eyelid (ptosis): One or both eyelids may sag.
Double vision (diplopia): Images may appear side by side or stacked. It often gets better when you close one eye.
Blurry vision that comes and goes

Face and throat symptoms

Mayo Clinic reports that in about 15% of people, the first symptoms involve the face and throat. These can include:

Speech that sounds soft, slurred or nasal
Trouble swallowing, or choking more easily
Liquid coming out of your nose when you drink
Tired jaw muscles when chewing, especially with tough foods like steak
Changes in facial expression, such as trouble raising your eyebrows or holding a smile

Other Myasthenia Gravis Symptoms

As MG progresses or becomes generalized, weakness can spread to other muscles.

Neck weakness

Weak neck muscles can make it hard to hold your head up. This often shows up later, as MG gets worse.

Arm and leg weakness

You may notice:

Trouble lifting your arms over your head
Weak grip
Trouble climbing stairs or getting up from a chair
A change in the way you walk

Breathing muscles

MG can weaken the muscles that help you breathe. This can cause shortness of breath, especially when lying flat or after activity. Breathing changes always need prompt medical attention.

What Makes Symptoms Worse?

Many things can make MG weakness flare up. According to Mayo Clinic and the Myasthenia Gravis Foundation of America (MGFA), common triggers include:

Being tired or not sleeping well
Illness or infection
Heat
Stress
Surgery
Certain medicines, including some antibiotics, beta blockers and IV magnesium
Pregnancy and menstrual periods

Do not stop or change any medicine on your own because of this list. Talk with your doctor or pharmacist. They can look at what you take and decide what is safe for you.

Myasthenic Crisis: When to Call 911

A myasthenic crisis happens when the muscles you use to breathe become too weak to work well. It is a medical emergency. Some people need a breathing machine (ventilator) for a time.

NINDS reports that about 15% to 20% of people with MG have at least one crisis. Infection, stress, surgery and medicine reactions can set it off. But up to half of the time, no clear trigger is found.

Warning signs of a crisis

The MGFA lists these warning signs that breathing muscles are getting weak:

Feeling short of breath when lying flat
Fast, shallow breathing
Needing to stop mid-sentence to take a breath
A weak cough, or trouble clearing mucus or saliva
Speech that is getting more slurred
Trouble chewing or swallowing that is getting worse
Trouble holding your head up
Arm or leg weakness that is getting worse along with shortness of breath
Muscles between the ribs, in the neck or in the belly pulling in with each breath
Not being able to count to 20 out loud in one breath

Call 911 or go to the nearest emergency room right away if you:

Feel short of breath or are struggling to breathe
Cannot swallow or are choking on saliva
Cannot cough strongly enough to clear your throat
Feel too weak to speak or hold your head up

Do not wait to see if it passes. Do not drive yourself.

A pulse oximeter reading may look normal even when breathing muscles are getting weak. The MGFA notes that a low reading is a late sign in MG. Trust how you are breathing, not just the number.

Tell the emergency team you have myasthenia gravis. Bring your medicine list if you can, and ask them to contact your neurologist.

When to See Your Doctor

Not every symptom is an emergency. But some changes should be checked soon. Make an appointment if you notice:

New droopy eyelids or double vision
New trouble chewing, swallowing or speaking
Weakness that gets worse through the day
Trouble walking, using your arms or holding your head up
Your usual MG symptoms getting worse over days or weeks

It can help to keep a simple symptom log. Write down what you notice, what time of day it happens and what you were doing. Photos of a droopy eyelid at different times of day can also help your doctor.

Frequently Asked Questions

What is usually the first symptom of myasthenia gravis?

For many people, the first sign is a droopy eyelid or double vision. Mayo Clinic notes that more than half of people with MG first notice eye symptoms. Others first notice trouble chewing, swallowing or speaking.

Do myasthenia gravis symptoms come and go?

Yes. Symptoms often change from hour to hour and day to day. Most people feel strongest in the morning and weaker as the day goes on, especially after using the affected muscles.

Does myasthenia gravis cause pain?

MG is mainly a condition of muscle weakness, not pain. If you have new or severe pain, talk with your provider so they can look for the cause.

Can stress make myasthenia gravis symptoms worse?

Yes. Stress is a known trigger for flares. Rest, steady routines and getting help with tasks may ease the load on your body.

The Bottom Line

The main myasthenia gravis symptoms are droopy eyelids, double vision and weakness that worsens with use and improves with rest. Weakness can also affect chewing, swallowing, speech, the neck, arms, legs and breathing muscles. Infections, heat, stress and some medicines can make symptoms worse. Shortness of breath or trouble swallowing can signal a myasthenic crisis, so call 911 right away.