Myasthenia gravis (MG) is a chronic autoimmune neuromuscular condition that causes fluctuating muscle weakness and abnormal muscle fatigability (muscles get weaker the more you use them, then improve with rest). It happens when the immune system produces antibodies that disrupt communication between nerves and muscles at the neuromuscular junction, the microscopic “handover point” where nerve signals trigger muscle contraction.
In a healthy neuromuscular junction, nerves release a chemical messenger called acetylcholine. Acetylcholine binds to receptors on the muscle, creating an electrical response that leads to contraction. In myasthenia gravis, antibodies interfere with this process, most commonly by targeting the acetylcholine receptor, or by targeting proteins that help organise and stabilise those receptors. The end result is that the muscle receives a weaker signal and can struggle to sustain force, particularly with repeated activity.
Myasthenia gravis can affect different muscle groups, including those controlling eye movements (causing drooping eyelids and double vision), facial expression, speech and swallowing, and breathing. Some people experience symptoms limited to the eyes (ocular myasthenia), while others develop more widespread involvement (generalised myasthenia). Symptom patterns can change over time, and triggers like infection, stress, poor sleep, overheating, or certain medications may worsen weakness.
While there is no cure, many people live well with myasthenia gravis using a combination of medical management and rehabilitation. Physiotherapy for myasthenia gravis focuses on safe activity, fatigue management, mobility and balance, breathing support when needed, and maintaining independence during fluctuations. Physiotherapists also help people understand “how to train without overdoing it”, because myasthenia gravis requires a different approach to exercise than many other conditions.
Key Facts
- Australian estimates using PBS medication data suggested around 2,600 Australians were living with myasthenia gravis in 2009, equivalent to about 12 cases per 100,000 population, with a higher prevalence in females than males. 🔗
- In generalised myasthenia gravis, acetylcholine receptor antibodies are present in about 85% of patients, making this the most common antibody subtype. 🔗
- The MGFA Clinical Classification (Classes I to V) is widely used to describe disease severity and distribution, including identification of myasthenic crisis (Class V). 🔗
- Myasthenia gravis symptoms and impacted muscle groups commonly include eyes, face, throat and diaphragm, affecting vision, swallowing and breathing.
Risk Factors
- Thymus abnormalities (enlargement or thymoma) identified on medical assessment
- Female sex in younger adulthood and male sex in older adulthood (common age-pattern seen clinically in MG)
- Personal history of other autoimmune conditions (MG can co-occur with other autoimmune diagnoses in some people)
- Recent infection, surgery, or major stressor, which can precipitate symptom recognition or flare in vulnerable people
Symptoms
- Drooping eyelids (ptosis), which may be one-sided or both sides and often worsens later in the day
- Double vision (diplopia) due to weakness of the muscles that move the eyes
- Speech changes (dysarthria), such as slurred speech or a nasal voice, especially after talking for a while
- Swallowing difficulty (dysphagia), coughing or choking with meals, or unexplained weight loss
- Facial weakness, reduced facial expression, or difficulty chewing tougher foods
- Arm weakness (for example difficulty lifting overhead, carrying shopping, blow-drying hair) that worsens with repetition
- Leg weakness, difficulty climbing stairs, getting up from a chair, or reduced walking endurance
- Shortness of breath or reduced exercise tolerance, especially when lying down, during infections, or at the end of the day
- Overall fatigue that is out of proportion to the task and improves with rest
Aggravating Factors
- Repetitive activity of the same muscle group (for example prolonged talking, chewing, or sustained overhead work), which can trigger weakness more quickly
- Heat and overheating, including hot weather, hot showers, or exercising in warm conditions
- Infections and poor sleep, which can temporarily worsen weakness and breathing fatigue
- Emotional or physical stress, including recovery from surgery or major life events
- Certain medications that may worsen neuromuscular junction transmission in some people with MG
Causes
Myasthenia gravis is an autoimmune condition. That means the immune system mistakenly targets the body’s own tissues. In MG, the target is the neuromuscular junction, where the nerve communicates with the muscle. Several antibody patterns are recognised, and the antibody type can influence which muscles are affected, how symptoms present, and which treatments may be most effective.
- Acetylcholine receptor (AChR) antibody MG is the most common form. These antibodies reduce the number and function of working acetylcholine receptors on the muscle side of the neuromuscular junction. With fewer effective receptors, the muscle’s response becomes weaker, particularly with repeated activity. Many people with AChR-positive MG have thymus gland abnormalities, which is why the thymus is often assessed as part of MG work-up.
- MuSK antibody MG is less common and involves antibodies to muscle-specific kinase (MuSK), a protein involved in organising receptors at the neuromuscular junction. People with MuSK-positive MG can experience prominent bulbar symptoms (speech and swallowing difficulty) and may fatigue quickly with breathing and talking tasks.
- LRP4 antibody MG is another recognised pattern, and some people have MG symptoms without detectable AChR, MuSK or LRP4 antibodies (sometimes described as seronegative MG). Regardless of antibody type, the functional problem is similar: the nerve signal does not reliably drive muscle contraction.
The thymus gland is an important part of MG assessment. The thymus helps shape immune function, and in some people with MG it may be enlarged or contain a thymoma (a thymus tumour). Thymus-related issues can contribute to immune dysregulation and are one reason thymectomy may be considered in selected patients.
Myasthenia gravis is not contagious. It is not caused by exercise, diet, or lifestyle choices. However, lifestyle factors can influence symptom control. Physiotherapists commonly help patients identify practical triggers (overheating, poor pacing, prolonged sustained tasks) and create day-to-day strategies to reduce flare-ups while maintaining an active, healthy routine.
How Is It Diagnosed?
Myasthenia gravis is diagnosed by a medical team, usually involving a neurologist. Diagnosis combines your symptom history (especially fluctuating weakness that worsens with use), physical examination, antibody testing, and specialised studies of neuromuscular transmission.
Because MG can affect eyes, speech, swallowing and breathing, assessment often includes targeted questioning about double vision, drooping eyelids, chewing fatigue, choking episodes, voice changes, shortness of breath, and the timing of symptoms across the day. The classic MG pattern is that symptoms are better in the morning and worsen later in the day, but this is not universal.
A key part of diagnosis is distinguishing MG from conditions that can look similar, such as thyroid eye disease, motor neurone disease, stroke, brainstem disorders, muscular dystrophies, or Lambert-Eaton myasthenic syndrome. Investigations help confirm impaired neuromuscular junction transmission and identify the underlying antibody type where possible.
Physiotherapists do not diagnose MG, but they play a valuable role in the broader pathway. Physiotherapy assessment can document baseline strength, walking tolerance, breathing effort, posture and balance, then help plan safe activity while medical treatments are being established.
Investigations & Imaging
- Blood tests: AChR, MuSK and other MG-related antibodies
- Helps identify the MG subtype and supports diagnosis. Antibody type can influence symptom patterns and management planning.
- Repetitive nerve stimulation (RNS)
- Assesses neuromuscular junction transmission by looking for a characteristic decrement in muscle response with repeated stimulation.
- Single-fibre electromyography (SFEMG)
- A sensitive test that measures ‘jitter’ in neuromuscular transmission and is often used when diagnosis is uncertain.
- CT or MRI chest (thymus assessment)
- Checks for thymus enlargement or thymoma, which may influence treatment decisions such as thymectomy.
- Pulmonary function tests (including measures like FVC) when breathing is affected
- Assesses respiratory muscle strength and helps guide respiratory monitoring and crisis planning.
- Swallowing assessment (speech pathology, and sometimes imaging-based studies)
- Assesses safety of swallowing if choking, coughing with meals, or weight loss is present.
Grading / Classification
- Ocular myasthenia gravis
- Weakness limited to eye muscles, typically causing ptosis and/or double vision. Physiotherapy input often focuses on pacing, neck posture strategies (to reduce compensation strain), and safe activity planning while medical management is optimised.
- Generalised myasthenia gravis
- Weakness affects muscles beyond the eyes, such as face, throat, limbs and sometimes breathing muscles. MG rehab is broader, commonly including strength and endurance planning, mobility and balance work, respiratory strategies, and falls prevention.
- Myasthenic crisis
- A medical emergency involving significant respiratory weakness requiring urgent medical care, sometimes ventilatory support. Physiotherapy may contribute to respiratory monitoring education and early escalation plans.
- MGFA Clinical Classification (Classes I to V)
- A widely used grading system describing distribution and severity. Class I is ocular-only. Classes II to IV describe mild to severe generalised weakness. Class V identifies myasthenic crisis requiring intubation or ventilatory support.
Physiotherapy Management
Physiotherapy for myasthenia gravis is about maintaining function without provoking excessive fatigue. Because MG weakness fluctuates, your physiotherapist will typically assess you on both a “good day” and a “bad day” if possible, then build a flexible plan that adapts to symptom changes. Your program should feel sustainable, not punishing.
MG physiotherapy commonly focuses on:
- Function and safety: walking ability, stairs, transfers, balance, falls risk and safe community mobility.
- Fatigue management: pacing, task breakdown, energy conservation and planning around medication timing.
- Respiratory support (when relevant): breathing efficiency, chest mobility, airway clearance strategies and escalation planning.
- Musculoskeletal secondary issues: neck, shoulder and back pain from compensation (for example, chin-up posture with ptosis, or bracing with balance insecurity).
Physiotherapists also work as part of a multidisciplinary team, liaising with neurology, respiratory medicine, occupational therapy, speech pathology and dietetics when swallowing and weight maintenance are affected.
Exercise
Myasthenia gravis physiotherapy exercises should be tailored to your symptom pattern, antibody subtype, and daily demands. In MG, the goal is usually to improve function and endurance without triggering prolonged fatigue or a symptom crash.
- Strengthening
Physiotherapists often use low-to-moderate intensity strengthening with careful pacing, longer rest intervals, and symptom monitoring. The focus is frequently on muscles that support function, such as hip and thigh muscles for stairs and rising from a chair, calf and ankle control for walking stability, and shoulder blade and trunk endurance for posture. If bulbar or respiratory muscles are affected, the program will prioritise safety and medical guidance rather than pushing intensity. - Functional training
Instead of purely gym-based exercises, MG rehab often uses task-specific practice, such as sit-to-stand repetitions with planned rests, step-ups with controlled tempo, and short, structured walking intervals. This helps translate exercise into daily life, which matters when symptoms fluctuate. - Aerobic exercise
Many people with MG benefit from gentle-to-moderate aerobic activity (for example stationary cycling, walking on flat ground, or water-based exercise) as tolerated. A physio will usually recommend shorter bouts with rest breaks, building total weekly volume gradually rather than doing one long session that wipes you out. - Flexibility and mobility
Stretching is used to manage stiffness and secondary tightness from altered movement patterns, especially if you are protecting weak muscles or adopting compensatory postures. Stretching is not a primary treatment for MG itself, but it can improve comfort and movement efficiency.
A practical physiotherapy tip for MG is timing. Many people exercise when their medication is working best or when their daily energy is highest, then plan rest afterwards. Your physiotherapist can help you test and refine that routine.
Activity Modification
Activity modification in MG is one of the most powerful tools for staying independent. Physiotherapists commonly teach energy conservation, which is not about avoiding activity. It is about using your energy in a way that matches how MG behaves.
Examples of MG-specific activity modification include:
- Task chunking
Breaking activities into smaller parts (for example, shower then rest, dress then rest, breakfast then rest) to prevent a rapid fatigue spiral. - Alternating muscle groups
Switching between tasks that use different muscles (for example, avoid doing prolonged overhead work immediately after stairs). - Reducing sustained postures
MG often worsens with sustained holds. Your physio may recommend strategies such as sitting for grooming, using a perching stool in the kitchen, or setting timers for short “movement blocks” rather than long, continuous effort. - Heat management
Exercising in cool environments, using fans, wearing breathable clothing, and avoiding hot showers before exertion can reduce symptom flare for people sensitive to heat. - Equipment as an energy saver
Walking aids, shower chairs, and stair rails can reduce the energy cost of daily life. In MG, using supports early can allow you to keep doing meaningful activities instead of burning all your energy on basic tasks.
Manual Therapy
Manual therapy in myasthenia gravis is aimed at secondary musculoskeletal problems rather than the autoimmune process. Many people with MG develop aches and pains from compensation. For example, a person with ptosis may lift their chin and overuse neck muscles to see, or a person with balance insecurity may brace through the back and shoulders.
Physiotherapists may use gentle soft tissue techniques and joint mobilisation to help manage neck and upper back tightness, shoulder discomfort, and thoracic stiffness that can make breathing feel more effortful. Manual therapy can also help you tolerate posture retraining and exercise, particularly when stiffness is limiting movement quality.
In MG, manual therapy should be paired with an active plan. That might include posture changes, strengthening of supportive muscles, scheduled rest breaks, and breathing efficiency strategies if you are holding tension through the chest and shoulders.
Postural Retraining
Postural retraining can be very relevant in MG, especially when eye symptoms or fatigue drive compensations. Ptosis and double vision can lead to a persistent chin-up posture, forward head position, and shoulder tension. Over time, that can trigger headaches, neck pain, and upper back stiffness.
A physiotherapist may address posture by improving thoracic mobility, strengthening the upper back and shoulder blade stabilisers, and teaching practical set-ups for reading and screens. Small changes such as screen height, lighting, and seating support can reduce the need to strain the neck and eyes.
If limb weakness affects walking or transfers, posture retraining also includes trunk control and safe movement strategies. Better trunk control can reduce falls risk and make walking more efficient, which matters when MG limits your energy budget.
Bracing & Taping
Bracing and taping are not routine for every person with MG, but they can be useful when limb weakness affects joint stability and walking safety. A physiotherapist may recommend ankle braces or supportive footwear if ankle control is inconsistent, or trial a walking aid to reduce trips and falls.
For some people, a simple mobility aid (like a single-point cane for longer distances) can reduce the overall energy cost of walking and help prevent the end-of-day deterioration that leads to near misses. Bracing decisions in MG are usually conservative and focused on function, because symptoms can fluctuate. Your physiotherapist will help you choose the lightest, simplest support that improves safety without making you dependent on it unnecessarily.
Taping may be used occasionally for proprioceptive support or comfort in an irritated joint, but it is not a primary MG treatment. If bracing is needed long-term, physiotherapists often collaborate with orthotists.
Heat & Ice
Heat and ice can help manage symptoms around muscle tension and secondary pain. Heat may relax tight muscles in the neck, jaw, shoulders or calves before stretching. However, because some people with MG notice symptom worsening with overheating, physiotherapists commonly recommend cooler strategies first if heat sensitivity is present.
Cooling strategies can include cool packs to the neck, a cool shower (not hot), fans during exercise, air conditioning, and hydration. Ice may help settle localised musculoskeletal soreness after an activity flare. The aim is to improve comfort and reduce the chance that pain becomes an additional driver of fatigue and inactivity.
Tens
TENS may be used in myasthenia gravis physiotherapy for secondary musculoskeletal pain, such as neck or back discomfort from compensation or prolonged sitting. TENS does not treat neuromuscular junction transmission, so it is an adjunct to help you stay active and tolerate posture and strengthening work.
In MG, physiotherapists are careful to ensure TENS use does not distract from the main plan: pacing, functional exercise, posture, and respiratory monitoring when required. If you have reduced sensation in an area or fragile skin from medications, your physiotherapist will modify or avoid TENS accordingly.
Education
Education is central to MG rehab because day-to-day decisions strongly influence symptom control. Physiotherapists educate patients and families on how MG fatigue works, how to recognise early warning signs of overdoing it, and how to plan activity so you can keep participating in life.
Common education topics in myasthenia gravis physiotherapy include:
- Pacing
Using planned rests before exhaustion, and setting realistic “stop points” rather than pushing until you fail. - Trigger planning
Managing heat, illness, and stress, and building a plan for times when symptoms worsen. - Falls prevention
Safe turning strategies, lighting and trip hazard reduction at home, and appropriate footwear. - Breathing awareness
Recognising red flags such as rapid breathing at rest, inability to speak in full sentences, or marked breathlessness lying down, and knowing when to seek urgent care. - Medication awareness
Understanding that some medications can worsen MG symptoms, and that new prescriptions should be discussed with your medical team.
Other
Other physiotherapy strategies in MG often include:
- Respiratory physiotherapy:
If breathing muscles are involved, physiotherapists can help with chest wall mobility, breathing pattern retraining, supported cough techniques, and airway clearance strategies. They also help patients understand when to escalate care, especially during infections. - Balance and gait training:
For limb weakness and reduced endurance, physiotherapists prescribe balance exercises, walking retraining, and strategies to reduce trips and conserve energy during community mobility. - Functional equipment and home set-up:
Physiotherapists may recommend rails, shower chairs, mobility aids, and safe transfer strategies, often in collaboration with occupational therapy. - Swallowing safety support:
Physiotherapists do not treat swallowing directly, but they can identify risk patterns (fatiguing during meals, coughing, breathlessness) and support prompt referral to speech pathology while advising on posture and fatigue pacing around meals.
Other Treatments
Medical management for myasthenia gravis is individualised and often involves a combination of treatments. Common medication groups include anticholinesterase medications (such as pyridostigmine) to improve neuromuscular junction transmission, and immunotherapies (including corticosteroids and other immunosuppressants) to reduce autoimmune activity.
For significant symptom worsening, severe bulbar involvement, or myasthenic crisis, hospital-based treatments such as intravenous immunoglobulin (IVIG) or plasmapheresis may be used to reduce circulating antibodies. Newer targeted therapies may also be considered in specialist settings depending on disease subtype and severity.
Importantly, some medications can worsen MG symptoms in susceptible individuals. Patients are often advised to discuss new medications with their prescribing team, particularly antibiotics and cardiovascular medications known to potentially exacerbate MG in some cases. Symptom changes after a new medication should be reviewed promptly.
Physiotherapy works alongside medical treatment by supporting safe function, preventing deconditioning, reducing falls risk, and helping people return to activity after hospital admissions, crises, or medication changes.
Surgery
Thymectomy (surgical removal of the thymus) may be recommended for some people with myasthenia gravis, particularly if a thymoma is present, or in selected patients with generalised AChR-positive MG based on specialist guidance. Thymectomy does not guarantee remission, but it can lead to symptom improvement and may reduce medication requirements in some patients over time.
Physiotherapy is often part of pre- and post-operative care. Before surgery, physiotherapists may focus on respiratory preparation, posture, and safe activity planning. After surgery, physiotherapists assist with breathing exercises, gradual return to walking and daily function, shoulder mobility and posture (particularly after chest surgery), and pacing to avoid overexertion while healing.
Prognosis & Return to Activity
Myasthenia gravis prognosis varies widely. Many people respond well to treatment and live full lives. Symptoms often fluctuate, particularly early after diagnosis, and many people learn over time how to balance activity, rest, and medication timing. Some people experience long periods of stability, and a subset achieve remission or minimal symptoms with ongoing management.
Prognosis is influenced by factors such as antibody type, early bulbar or respiratory involvement, thymus abnormalities, and how quickly effective treatment is established. While life expectancy is normal for many people with MG, myasthenic crisis remains a serious complication, particularly during infections or significant stressors.
Return to activity is usually achievable, but it should be planned. Physiotherapists help people with MG return to walking programs, gym-based strength work, hydrotherapy, and community participation using pacing principles. The most successful MG rehab plans are flexible and prioritise consistency over intensity. If you can train regularly without a crash, you are far more likely to maintain strength and independence long-term.
Complications
- Myasthenic crisis with significant breathing weakness requiring emergency care and possibly ventilatory support
- Aspiration (food or fluid going into the airway) due to swallowing fatigue, increasing risk of pneumonia
- Falls and injury related to fluctuating limb weakness and fatigue
- Weight loss and dehydration when chewing and swallowing become too tiring
- Medication side effects, including issues related to long-term immunosuppression, which may indirectly affect strength, bone health, and recovery capacity
Preventing Recurrence
- Use pacing as a prevention strategy by planning rest breaks before you are exhausted, because MG weakness builds with repeated activity and can trigger avoidable flare-ups
- Reduce overheating: exercise in cool conditions, avoid hot showers before exertion, and use cooling strategies if heat worsens your MG symptoms
- Treat infections early and have an illness plan, as respiratory infections can worsen MG weakness and increase crisis risk
- Review new medications with your medical team and monitor for symptom change after starting something new, because some drugs can worsen neuromuscular junction transmission
- Maintain a consistent, physiotherapist-guided strengthening and walking program to prevent deconditioning, which can otherwise make MG fatigue feel more disabling
When to See a Physio
- If limb weakness, balance changes, or fatigue are affecting walking, stairs, transfers, or your confidence moving in the community
- If you want a tailored myasthenia gravis physiotherapy exercise plan that improves function without triggering symptom crashes
- If you are having frequent near falls, feel unsteady, or have reduced foot/ankle control on uneven ground
- If neck, shoulder, or back pain is building due to compensation for eye symptoms or fatigue-based posture changes
- If you have had a hospital admission, medication change, or flare-up and need a staged return to activity plan
- If breathing feels more effortful, your cough is weaker, or colds are lingering, so respiratory physiotherapy input and escalation planning can be considered