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Understanding Myasthenia Gravis

  • Writer: Ben Proctor
    Ben Proctor
  • 3 days ago
  • 3 min read


As a physiotherapist, I often meet people who have questions about rare neurological conditions like Myasthenia Gravis (MG). It’s an important condition to understand, especially because it can cause very real challenges to day-to-day life. Let’s explore what MG is, its history, symptoms, how it’s diagnosed, and how it can be managed medically and through supportive care.


What is Myasthenia Gravis?


Myasthenia Gravis is a chronic autoimmune neuromuscular disorder that causes weakness in the skeletal muscles—the muscles your body uses for movement. The word itself comes from Greek and Latin roots: myo (muscle), asthenia (weakness), and gravis (serious or grave).


In MG, the body’s immune system mistakenly attacks the acetylcholine receptors (AChRs) at the neuromuscular junction—the point where nerves communicate with muscles. This disruption prevents efficient transmission of nerve signals, leading to muscle weakness that typically worsens with activity (fatigability) and improves with rest.


A Brief History of MG


  • 1672: The first possible case was described by Thomas Willis, an English physician.

  • 1877: The term myasthenia gravis was introduced by German physicians Erb and Goldflam.

  • 1895: Samuel Goldflam published one of the first detailed case studies.

  • 1934: Mary Walker, a British doctor, discovered that the drug physostigmine (a cholinesterase inhibitor) temporarily improved symptoms—this was a breakthrough in understanding treatment.

  • Since then, advances in immunology and neurology have transformed MG from a once life-threatening disease into a manageable chronic condition.


Signs and Symptoms


MG can affect different muscle groups, and symptoms vary from person to person. Key features include:


  • Eye muscles (ocular MG): Drooping eyelids (ptosis) and double vision (diplopia).

  • Facial muscles: Difficulty smiling, chewing, swallowing, or speaking clearly.

  • Neck and limb muscles: Trouble holding up the head, lifting arms, or climbing stairs.

  • Breathing muscles (in severe cases): This can lead to a life-threatening condition known as a myasthenic crisis.

Hallmark feature: Weakness worsens with activity and improves with rest.


Causes and Risk Factors


MG is an autoimmune disease. The body produces antibodies that block or destroy the acetylcholine receptors or related proteins (such as MuSK – muscle-specific kinase). This prevents proper muscle activation.


Possible contributing factors:


  • Genetic predisposition

  • Thymus gland abnormalities (tumours or hyperplasia are common in MG patients)

  • Environmental or immune triggers (not fully understood)


MG affects men and women differently: it tends to appear in women under 40 and men over 60, though it can occur at any age.


Diagnosis


Diagnosing MG requires a combination of clinical evaluation, special tests, and lab work:


  • Physical exam: Looking for fatigable weakness, especially in eye and facial muscles.

  • Blood tests: Detecting MG-related antibodies (AChR, MuSK).

  • Electromyography (EMG): Measures electrical activity of muscles and detects impaired nerve-to-muscle transmission.

  • Ice pack test: Placing an ice pack on a drooping eyelid often improves ptosis temporarily—simple but useful.

  • CT or MRI scan: To check for thymus abnormalities.

  • Pulmonary function tests: To assess breathing capacity in severe cases.


Medical Management


While there is currently no cure, MG can be managed effectively. Treatments aim to improve communication at the neuromuscular junction and reduce the immune attack.


1. Medications


  • Cholinesterase inhibitors (e.g., pyridostigmine): Improve nerve-to-muscle signal transmission.

  • Immunosuppressants (e.g., corticosteroids, azathioprine, mycophenolate): Reduce immune activity.

  • Biologic therapies (e.g., rituximab, eculizumab): Used in severe or resistant cases.


2. Thymectomy


Surgical removal of the thymus gland can improve symptoms or even lead to remission in some patients.


3. Plasma Exchange (Plasmapheresis) and IV Immunoglobulin (IVIG)


These are short-term treatments used during severe flare-ups or crises. They work by removing or neutralising harmful antibodies.


4. Lifestyle & Supportive Care


  • Balancing rest and activity (avoid over-exertion)

  • Using eye patches for double vision

  • Speech and swallow therapy if needed

  • Regular check-ups with a neurologist and multidisciplinary team


Living with MG


Most people with MG can live full lives with proper treatment and support. Education, pacing, and open communication with healthcare providers are essential. A strong support network—family, friends, and patient communities—can make a big difference.


Useful Resources for Patients



References


  1. Gilhus, N. E. (2016). Myasthenia Gravis. New England Journal of Medicine, 375(26), 2570–2581.

  2. Meriggioli, M. N., & Sanders, D. B. (2009). Autoimmune myasthenia gravis: emerging clinical and biological heterogeneity. The Lancet Neurology, 8(5), 475–490.

  3. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov

  4. Myasthenia Gravis Foundation of America. https://myasthenia.org

 
 
 

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