Myasthenia Gravis
What Is Myasthenia Gravis?
Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder that causes weakness in the skeletal muscles—the muscles your body uses for movement. The name comes from Latin and Greek, meaning “grave muscle weakness,” though with proper treatment, many people with MG lead normal or near-normal lives.
In MG, the immune system mistakenly produces antibodies that interfere with the communication between nerves and muscles, leading to muscle fatigue and weakness that typically worsens with activity and improves with rest.
What Causes It?
In most cases, MG is caused by antibodies that attack acetylcholine receptors (AChR) at the neuromuscular junction—the place where nerve cells signal muscles to move. Some patients may have antibodies against other proteins involved in this process, such as:
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MuSK (Muscle-Specific Kinase)
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LRP4 (Low-Density Lipoprotein Receptor-Related Protein 4)
These antibodies block or destroy the receptors needed for muscle contraction, preventing normal muscle activation.
Who Can Get Myasthenia Gravis?
MG can affect anyone, but it is most commonly diagnosed in:
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Women under 40
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Men over 60
It can also occur in children (called juvenile MG) and may be associated with thymus gland abnormalities, including tumors (thymomas) in some cases.
Common Symptoms
Symptoms can vary widely, but the hallmark is muscle weakness that worsens with use and improves with rest. Common signs include:
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Drooping eyelids (ptosis)
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Double vision (diplopia)
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Difficulty swallowing, chewing, or speaking
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Weakness in the arms, legs, or neck
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Shortness of breath or difficulty breathing in severe cases
Symptoms may be mild or severe, and can fluctuate from day to day.
How Is It Diagnosed?
Diagnosis typically involves:
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Blood tests for antibodies (AChR, MuSK, or LRP4)
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Electromyography (EMG) to measure electrical activity in muscles
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Imaging (CT or MRI) to check for thymus abnormalities
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Physical exam and review of symptom patterns
Is It Treatable?
Yes. While there is no cure, effective treatments are available to manage symptoms and improve quality of life:
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Medications such as pyridostigmine (improves muscle strength)
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Immunosuppressants (e.g., corticosteroids, azathioprine)
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IVIG or plasmapheresis for severe cases or flares
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Thymectomy (surgical removal of the thymus gland), especially if a thymoma is present
With proper management, many people with MG are able to lead full and active lives.
Summary
Myasthenia gravis is an autoimmune disorder that disrupts communication between nerves and muscles, causing muscle weakness and fatigue. While it can be a challenging condition, early diagnosis and treatment can significantly improve outcomes. If you're experiencing symptoms like drooping eyelids, double vision, or unexplained muscle weakness, talk to your doctor about getting tested for MG.
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Biomarkers related to this condition:
The AChR Binding Antibodies, Serum test measures the presence of autoantibodies against acetylcholine receptors (AChRs) in the blood. These antibodies interfere with the normal communication between nerves and muscles and are commonly associated with
Learn moreWhat Are AChR Blocking Antibodies? AChR Blocking Antibodies are a type of autoantibody that interfere with how acetylcholine receptors (AChRs) work at the neuromuscular junction—the place where nerves signal muscles to contract. These antibo
Learn moreWhat Is the AChR-Modulating Antibody? The AChR-Modulating Antibody test detects autoantibodies that disrupt communication between nerves and muscles by targeting and altering acetylcholine receptors (AChRs) on muscle cells. These antibodies are co
Learn moreWhat Is the MuSK Antibodies Test? The MuSK Abs, Serum test detects antibodies against Muscle-Specific Kinase (MuSK) in your blood. These antibodies are associated with a type of autoimmune myasthenia gravis (MG)—a condition that causes muscl
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