Myasthenia Gravis is a chronic autoimmune neuromuscular disorder characterised by fluctuating muscle weakness and fatigue. It occurs when the immune system produces antibodies that disrupt communication between nerves and muscles, particularly at the neuromuscular junction. This interference impairs the transmission of important neurotransmitters (acetylcholine) essential for muscle contraction. The condition can affect various muscle groups, including those controlling eye movements, facial expressions, swallowing, and breathing. The severity and progression of symptoms vary among individuals, and while there is no cure, effective treatments are available to manage the condition.
Signs & Symptoms
Symptoms often fluctuate in intensity and may worsen with activity and improve with rest. Common siThe main sign of Myasthenia Gravis is muscle weakness that gets worse with activity and improves with rest. The symptoms can vary widely between individuals, but commonly include:
- Drooping eyelids (ptosis), often on both sides but can be one-sided
- Double vision (diplopia), due to weakness of the muscles that move the eyes
- Difficulty speaking (dysarthria), especially after talking for a while
- Trouble swallowing (dysphagia), which may lead to choking or weight loss
- Weakness in the arms or legs, making it hard to lift objects, climb stairs, or walk
- Shortness of breath, especially when lying down or after physical activity
In some cases, symptoms may be limited to the eyes (ocular Myasthenia). In others, they may affect many muscle groups (generalised Myasthenia).
Causes & Contributing Factors
Myasthenia Gravis is an autoimmune condition, which means the immune system attacks healthy parts of the body by mistake. In this case, it targets the neuromuscular junction—the point where nerves signal muscles to contract.
There are several known antibody types involved:
- Acetylcholine Receptor (AChR) Antibodies: Found in about 85% of cases. These antibodies attack the receptors that receive messages from nerves. Without enough working receptors, the muscle can’t receive the signal properly, leading to weakness.
- Muscle-Specific Kinase (MuSK) Antibodies: Seen in a smaller group of people. MuSK is a protein that helps organise the muscle receptors. When it’s blocked, muscles—especially those involved in breathing, swallowing, and speaking—can become weak.
- LRP4 Antibodies: Less common, but also disrupt the nerve-muscle connection. This form often causes milder symptoms or mostly affects the eyes.
Other causes can include:
- Thymus Gland Problems: The thymus gland helps control the immune system, especially in early life. In many people with Myasthenia Gravis, the thymus is enlarged or contains a tumour (called a thymoma), which may lead the immune system to attack the neuromuscular junction.
- Environmental and Medication Triggers: Some factors can worsen symptoms or trigger the condition in vulnerable people. These include:
- Infections
- Stress (emotional or physical)
- Surgery
- Certain medications, such as:
- Antibiotics (e.g., aminoglycosides)
- Beta-blockers (used for heart conditions)
- Anaesthetics and magnesium-containing drugs
Classification
Myasthenia Gravis can be classified based on how much of the body it affects and the severity:
- Ocular Myasthenia – only eye muscles are involved
- Generalised Myasthenia – muscles beyond the eyes are affected
- Myasthenic Crisis – a serious complication involving breathing difficulties, requiring emergency care
The Myasthenia Gravis Foundation of America (MGFA) uses a grading system from I to V:
- Class I: Only eye muscles affected
- Class II–IV: Increasing involvement of other muscles
- Class V: Myasthenic crisis with need for a ventilator
Prognosis
Although Myasthenia Gravis is a chronic (long-term) condition, many people live well with proper treatment. With medications and lifestyle changes, most people can manage symptoms and lead full lives.
- The condition does not shorten life expectancy for most people.
- Some individuals may experience periods where symptoms improve or even go away (remission).
- Ongoing management is usually needed to prevent flare-ups.
Treatment
There is no cure, but several treatments can reduce symptoms and improve muscle strength. Management is usually tailored to the individual and may involve a mix of medication, physiotherapy, and sometimes surgery.
Medications
- Anticholinesterase agents (e.g., pyridostigmine): Help muscles respond better to nerve signals. Often the first-line treatment.
- Corticosteroids (e.g., prednisone): Reduce the immune system’s activity. Useful in more severe cases.
- Immunosuppressants (e.g., azathioprine, mycophenolate): Used to control the immune system longer term.
- Intravenous immunoglobulin (IVIG) and Plasmapheresis: Used in severe cases or myasthenic crisis. These treatments clean the harmful antibodies out of the blood or replace them temporarily.
Surgery
- Thymectomy (removal of the thymus gland): Often recommended, especially in younger adults or those with a thymoma. Can lead to symptom improvement or remission.
Physiotherapy and Rehabilitation
Physiotherapy plays a central role in supporting function, reducing complications, and maintaining independence—especially during periods of muscle weakness, fatigue, or functional decline. By tailoring interventions to the individual’s needs, physiotherapy can improve daily function and overall quality of life.
Energy conservation techniques
Physiotherapists provide guidance on pacing strategies that help manage daily activities without overexertion.
This includes education on how to break up tasks, alternate periods of activity and rest, prioritise important activities, and modify the environment to reduce unnecessary energy expenditure. These strategies can significantly reduce fatigue and enable participation in valued activities.
Gentle strengthening exercises
A personalised program of low-impact strengthening exercises—often using body weight, resistance bands, or light weights—can help maintain or even improve muscle strength without exacerbating fatigue.
Regular, graded exercise can lead to better endurance and improved functional capacity. Exercise has also been shown to have positive effects on mood, sleep, and cognitive clarity, all of which contribute to better quality of life.
Respiratory physiotherapy
For those experiencing breathing difficulties or reduced lung function, respiratory physiotherapy can be vital. Techniques such as airway clearance, breathing retraining, and inspiratory muscle training can assist in clearing mucus, preventing infections, and improving oxygenation.
Better respiratory function helps to reduce the energy cost of breathing, which can have a direct impact on fatigue levels and overall comfort.
Postural and balance training
If weakness affects the limbs or trunk, there may be significant impacts on posture, balance, and walking ability. Physiotherapists can provide targeted training to improve postural alignment, core stability, and dynamic balance.
This not only reduces the risk of falls, but also increases confidence in moving around safely—both indoors and in the community. Improved stability can enable greater activity levels, which feeds back into better muscle conditioning and social participation.
Lifestyle and Support
- Rest and pacing are essential—overworking muscles can worsen symptoms.
- Avoiding triggers like stress and illness can help prevent flare-ups.
Information is provided for educational purposes only. Always consult your physiotherapist or other health professional.
References
Gilhus, N. E., & Tzartos, S. (2021). Myasthenia gravis: A clinical and immunological overview. Nature Reviews Neurology, 17(3), 145–158. https://doi.org/10.1038/s41582-020-00440-5
Meriggioli, M. N., & Sanders, D. B. (2009). Autoimmune myasthenia gravis: Emerging clinical and biological heterogeneity. The Lancet Neurology, 8(5), 475–490. https://doi.org/10.1016/S1474-4422(09)70063-8
Clifford, K. M., & Hobson-Webb, L. D. (2019). Therapeutic advances in MuSK antibody myasthenia gravis. Current Treatment Options in Neurology, 21(2), 6. https://doi.org/10.1007/s11940-019-0543-8
Engels, E. A., & Pfeiffer, R. M. (2003). Malignant thymoma in patients with myasthenia gravis. The Lancet, 362(9388), 2103–2104. https://doi.org/10.1016/S0140-6736(03)15122-4
O’Connell, K. E., & Liewluck, T. (2022). Exercise and rehabilitation in myasthenia gravis: A clinical review. Archives of Physical Medicine and Rehabilitation, 103(6), 1234–1242. https://doi.org/10.1016/j.apmr.2021.09.024