Can Myasthenia Gravis Come and Go? Understanding Flares and Fluctuating Symptoms

by Dr. Jonas Witt
Medical Doctor

August 7, 2026

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8 minutes

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Table of Contents

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TL;DR

Yes. Myasthenia gravis symptoms can become better or worse during the day and over longer periods.
Weakness often becomes more noticeable after repeated activity or when someone is tired and may improve after rest.
Infections, stress, heat, surgery, and some medicines may contribute to worsening symptoms in some people.
A flare is a meaningful worsening beyond a person's usual pattern. Breathing or severe swallowing difficulties need urgent medical attention.
Experiences shared through mama health show that fluctuation can look very different from person to person and can help people feel less alone in what they are experiencing.

Can myasthenia gravis really come and go?

Yes. Myasthenia gravis symptoms can fluctuate considerably, even though MG itself is a long-term autoimmune condition.

One of the defining features of MG is fatigable muscle weakness. This means weakness can become more noticeable after repeated muscle use and may improve after rest.[1]

For some people, symptoms are relatively mild in the morning and become more noticeable later in the day. For others, the pattern is less predictable.

Fluctuation can affect different muscle groups.

For example:

one or both eyelids may droop more as the day progresses
double vision may appear after prolonged visual activity
chewing may become harder during a meal
speech may become quieter, nasal, or slurred after talking
climbing stairs may feel easier at one point in the day than another
arm, leg, or neck weakness may become more noticeable after repeated activity

Some people mainly experience symptoms around the eyes. You can read more about how ocular MG can affect the eyelids and vision.

For a broader overview, see mama health's guide to the different symptoms people with MG may experience.

Why do MG symptoms change throughout the day?

MG symptoms change because communication between nerves and muscles becomes less effective with repeated activity.

In MG, antibodies interfere with communication at the neuromuscular junction, where nerves send signals to muscles. As muscles are used repeatedly, that communication can become less effective, making weakness more noticeable.[2]

Rest can allow some strength to return.

This is why someone may be able to perform an activity at one point but find the same activity much more difficult later.

A voice may sound clear at the beginning of a conversation and become weaker after several minutes. Chewing may feel manageable at the beginning of a meal but increasingly tiring toward the end.

These changes are part of the recognised pattern of MG. They do not mean someone is being inconsistent or exaggerating their symptoms.

What does fluctuating MG feel like in everyday life?

People living with MG often describe having different levels of strength at different times, sometimes within the same day.

Experiences shared through mama health show how disruptive this unpredictability can be.

Across anonymised conversations from UK adults living with confirmed MG, recurring descriptions included:

starting the day with relatively more strength before weakness became more noticeable
a voice becoming weaker after prolonged conversation
chewing becoming harder toward the end of a meal
stairs becoming more difficult later in the day
having to change plans when strength changed unexpectedly
arranging demanding activities around stronger periods
resting before exhaustion became severe
finding it difficult to explain why something possible yesterday may not be possible today

Another recurring theme was the invisibility of MG.

Someone may appear well during a short appointment, conversation, or social activity while experiencing much greater weakness at another point in the day.

This can make the condition difficult for other people to understand.

What do people with MG share on the mama health app?

Shared experiences on mama health show that questions about fluctuation, triggers, and worsening symptoms are common among people living with MG.

People have described:

uncertainty about whether worsening weakness is simply a difficult MG day
concern about symptoms becoming worse after an infection
difficulty knowing whether heat is affecting their strength
frustration when other people do not understand fluctuating symptoms
questions about when a change is important enough to discuss with their care team

mama health brings together anonymized shared experiences alongside information from trusted medical sources.

This can help people reflect on their own experiences and prepare questions for a healthcare professional. It does not diagnose a flare, predict how MG will develop, or determine what medical action someone should take.

What is the difference between normal MG fluctuation and a flare?

Normal fluctuation is the expected variation in MG weakness, while a flare or exacerbation is a more meaningful worsening beyond someone's usual pattern.

There is no single number of hours or days that automatically defines a flare.

What matters is whether the symptoms represent a clear change from what is normal for that individual.

Possible signs of more significant worsening can include:

weakness becoming consistently more pronounced than usual
symptoms affecting additional muscle groups
everyday activities becoming substantially harder
swallowing becoming more difficult
speech becoming noticeably weaker
usual periods of rest no longer bringing the expected improvement

International MG guidance distinguishes ordinary symptom fluctuation from significant exacerbation and myasthenic crisis.[3]

Because baseline symptoms differ between individuals, it can be useful to record changes and discuss them with the MG care team.

A simple note might include:

what changed
when it happened
what activity happened beforehand
whether rest made a difference
whether there was an infection, new medicine, or unusual physical stress

The aim is not to interpret these notes medically yourself. They can simply provide useful context for a conversation with a healthcare professional.

What can trigger worsening MG symptoms?

Tiredness, infections, stress, heat, surgery, and some medicines may make MG symptoms worse in some people.

Triggers vary considerably between individuals.

A factor that affects one person strongly may have little effect on someone else.

Can infections worsen myasthenia gravis?

Yes. Infections are a recognized trigger for MG exacerbations.

Respiratory infections, urinary infections, and other illnesses can place additional stress on the body.

In one retrospective study examining 212 MG exacerbations, infection was the most frequently identified contributing factor and was recorded in about 30% of exacerbations in that cohort.[4]

Experiences shared through mama health also include people describing periods of increased weakness following colds, respiratory infections, and other illnesses.

This does not mean that every infection will cause an exacerbation.

If an infection is accompanied by a clear worsening of MG symptoms, it can be worth discussing the change with a healthcare professional.

Can heat make MG symptoms worse?

Yes. Heat can temporarily increase weakness in some people living with MG.

Hot weather, hot environments, and increases in body temperature have been associated with worsening neuromuscular weakness in MG.[5]

Heat sensitivity also appears in experiecnes shared through mama health.

Some people describe needing more rest during hot weather or noticing that activities become more difficult when temperatures rise.

Others may notice little difference.

Because responses vary, individual experiences are useful to record rather than assuming that a particular trigger affects everyone.

Can stress and poor sleep make MG feel worse?

Physical and emotional stress may contribute to increased weakness in some people with MG.

People sharing their experiences through mama health have described periods of poor sleep, emotional stress, bereavement, physical overexertion, and demanding life events alongside changes in their symptoms.

Clinical sources also recognize stress and tiredness as possible factors associated with worsening symptoms.[1]

Living with unpredictable physical ability can itself create emotional strain.

For more information, see mama health's guide to emotional wellbeing while living with myasthenia gravis.

Can medicines make MG symptoms worse?

Some medicines can worsen MG weakness in some people, so healthcare professionals should know when someone has myasthenia gravis.

Medicines associated with potential worsening include certain antibiotics, intravenous magnesium, beta-blockers, and several other drug groups.[6]

However, this does not mean that every medicine on a cautionary list must always be avoided.

Sometimes a medicine may still be the most appropriate option after a healthcare professional considers the potential benefits and risks.

Before starting a new medicine, people with MG can make sure that the prescriber, pharmacist, dentist, surgeon, or anaesthetist knows about their diagnosis.

For more detail, see mama health's overview of medicines that may need additional consideration in people with MG.

Can pyridostigmine wearing off feel like a flare?

The effect of pyridostigmine can wear off between doses, but this is not automatically the same as an MG flare.

Pyridostigmine works for a limited period, so some people notice weakness becoming more prominent as a dose wears off.[7]

Experiences shared with mama health include people describing clear changes in strength depending on the timing of medication.

However, medication-related fluctuations and a broader MG exacerbation are not necessarily the same thing.

Medication doses or timing should not be changed independently.

If symptoms regularly become difficult before the next dose, this can be discussed with the prescribing healthcare professional.

For more background, see mama health's guide to medications used by people living with myasthenia gravis.

When does worsening MG become an emergency?

Severe or rapidly worsening breathing or swallowing difficulties can indicate a myasthenic crisis and require emergency medical attention.

A myasthenic crisis occurs when muscle weakness seriously affects breathing. Severe swallowing and bulbar weakness may also be present.[8]

The NHS advises calling 999 for an ambulance if someone with MG develops worsening severe breathing or swallowing difficulties.[1]

Emergency warning signs can include:

severe or rapidly worsening breathlessness
difficulty taking a full breath
worsening difficulty breathing when lying down
severe difficulty swallowing
difficulty handling saliva
choking
rapidly worsening speech together with breathing or swallowing weakness
rapidly increasing neck or generalised weakness alongside breathing problems

Do not wait for very late signs such as blue lips or loss of consciousness.

If you are experiencing worsening severe breathing or swallowing difficulties now, call 999.

For more information about swallowing symptoms, see mama health's guide to swallowing difficulties associated with MG.

When should worsening symptoms be discussed with your MG care team?

A persistent or noticeable change from your usual MG pattern is worth discussing with your MG nurse, neurologist, GP, or another healthcare professional.

Examples you could raise include:

weakness remaining clearly worse than your usual level
new or worsening swallowing difficulties
repeated coughing or choking during meals
an infection occurring alongside noticeably increased weakness
symptoms repeatedly worsening during a planned medication reduction
difficult medication side effects
questions before surgery or anaesthesia
concerns about a new prescription

Different situations require different responses.

A healthcare professional can advise whether something needs routine review, earlier assessment, or urgent care.

Can MG symptoms disappear for a while?

Yes. Some people can have periods with very few symptoms, but short-term improvement is not necessarily remission.

Daily fluctuation can make someone feel almost symptom-free at one point and considerably weaker later.

That is different from clinical remission.

Remission describes a more sustained period with minimal or no symptoms. Long-term studies show that remission can occur in MG, although the course of the condition varies widely between individuals.[9]

A good day therefore does not mean MG has disappeared.

Likewise, a difficult day does not necessarily mean the condition is permanently getting worse.

How can people adapt to unpredictable MG symptoms?

Many people living with MG describe adjusting routines around the times when their strength is more reliable.

Shared experiences through mama health include:

planning demanding activities during stronger parts of the day
allowing time to recover between activities
taking breaks before exhaustion becomes severe
simplifying plans when weakness increases
explaining fluctuating symptoms to family, friends, or colleagues
recording changes to discuss at future appointments
preparing questions in advance of medical visits

These are shared experiences, not treatment recommendations.

What works for one person may not suit another.

The broader lesson from the mama health community is that flexibility often becomes part of everyday life with MG.

Someone may be able to do something comfortably one day and find it difficult the next.

Both experiences can be genuine.

How can collective experience help people living with MG?

Collective experience can give people language for experiences that are difficult to explain and show that others may face similar uncertainty.

A single story cannot tell someone what will happen with their own MG.

But a larger group of shared experiences can reveal recurring themes.

For example:

“Is this normal fluctuation or something more?”
“Why can I do this in the morning but not later?”
“Does anyone else become much weaker after being ill?”
“How do I explain to other people that my abilities change?”
“What questions could I bring to my next appointment?”

Seeing these themes can make an unpredictable condition feel less isolating.

mama health provides a space to explore anonymized experiences from other people living with MG alongside trusted educational information.

The aim is to support understanding and reflection, not to provide diagnosis, medical monitoring, treatment recommendations, or predictions.

What questions could you ask your MG care team?

Questions about your baseline, medicines, worsening symptoms, and emergency plan can make changes easier to discuss.

You could ask:

What does my usual MG baseline look like?
What changes would you want me to contact the team about?
Who can I contact if symptoms become noticeably worse between appointments?
Which medicines should other doctors, pharmacists, or dentists know may affect MG?
Is there an MG alert card or clinical letter I should carry?
What should I know before surgery, dental treatment, or anaesthesia?
What could I do if I develop an infection and my MG symptoms also become worse?
Which breathing or swallowing symptoms require emergency help?

Writing questions down beforehand may make them easier to remember during an appointment.

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This content is informational and not a medical device.

mama health offers information and support and does not replace a doctor.