Many people are likely seeking to learn more about myasthenia gravis (MG) following the recent news that tennis legend Monica Seles, a nine-time Grand Slam champion, revealed her diagnosis ahead of the US Open. In an interview with The Associated Press, Seles shared that symptoms such as double vision and muscle weakness began disrupting routine activities like doing her hair or playing catch with family. Now, she is using her platform to raise awareness about this often misunderstood condition.
What Is Myasthenia Gravis?
Myasthenia gravis is a rare, chronic autoimmune disorder targeting the neuromuscular junction, the connection between nerve endings and muscles. In MG, the immune system mistakenly produces antibodies that block or destroy acetylcholine receptors (AChR) on muscle cells. This impairs nerve signals and leads to muscle weakness that typically worsens with activity and improves with rest.
This autoimmune process often involves immunoglobulin G (IgG) antibodies, and may occasionally involve abnormalities of the thymus gland—either enlargement (hyperplasia) or tumors (thymomas).
How Many People Are Affected?
Though MG is considered rare, it affects more people globally than some might expect. Estimates suggest that approximately 12.4 per 100,000 people worldwide live with MG, based on meta-analysis data.
Other sources report prevalence ranging from 150 to 200 cases per million people (equivalent to 15–20 per 100,000). In the U.S., about 60,000 people are living with MG, or roughly 20 per 100,000 Americans. To put that rate into context, Parkinson’s disease has an incidence rate of around 60 per 100,000 persons according to the NIH.
Symptoms and Disease Course
Common Presentations
Ocular symptoms are often the first to appear in about two-thirds of patients, involving droopy eyelids (ptosis) and double vision (diplopia).
As MG progresses, it may become generalized, affecting facial muscles, limbs, and throat; symptoms can include:
- Muscle weakness and fatigue
- Difficulty speaking, chewing, and swallowing
- Trouble walking
- Respiratory compromise in severe cases
Symptoms characteristically worsen with exertion and improve with rest (a hallmark of MG).
Disease Fluctuations
MG is known for its variable course, marked by periods of exacerbation and remission. Some patients may experience nearly complete symptom resolution, at least temporarily.
Diagnosis
Diagnosing MG involves a combination of:
- Blood tests to detect autoantibodies (e.g., AChR, MuSK, LRP4)
- Neurophysiological studies, including repetitive nerve stimulation and single-fiber electromyography (EMG)
- Imaging (CT or MRI) to evaluate the thymus gland for abnormalities
Sometimes, clinicians also use a medication challenge (e.g., edrophonium) to assess improvement in muscle strength, though this is less common today.
Treatment and Management
While there’s no cure for MG, treatments can control symptoms and improve quality of life.
Symptomatic Therapy
Acetylcholinesterase inhibitors (e.g., pyridostigmine) enhance neuromuscular transmission by preventing breakdown of acetylcholine.
Immunosuppressive and Targeted Therapies
Corticosteroids and other immunosuppressants reduce antibody production and inflammation; many patients see marked improvement.
Targeted therapies include:
- Neonatal Fc receptor blockers (like efgartigimod alfa/Vyvgart), which reduce levels of pathogenic antibodies
- Monoclonal antibodies that target B-cells or components of the complement system, tailored to specific MG subtypes
Surgical and Emergency Interventions
Thymectomy (removal of the thymus) may induce remission or reduce disease severity, especially when thymomas are present or in early generalized MG cases.
Plasmapheresis (plasma exchange) and intravenous immunoglobulin (IVIG) provide temporary relief during myasthenic crises or for preparation before surgery.
Advanced Options
In rare, treatment-resistant cases, hematopoietic stem cell transplantation (HSCT) may offers preliminary evidence of long-term benefit.
With modern treatments, many individuals with MG lead full, active lives. Early in the 20th century, mortality rates were as high as 70%, largely due to respiratory complications. Today, mortality estimates range from 3–9%, reflecting significant progress in care.
However, about 20% of patients may experience a myasthenic crisis, a severe episode requiring urgent medical intervention—within the first two years of diagnosis.
Myasthenia gravis is a rare autoimmune condition characterized by fluctuating muscle weakness caused by disrupted nerve-to-muscle signaling. While there’s no cure yet, a range of medical and surgical treatments offer promising results. The recent public revelation by Monica Seles offers both awareness and inspiration for those affected—and reminds us all of the power of visibility and advocacy.
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