Myasthenia Gravis: Symptoms, Causes, Treatments, and More

Myasthenia gravis is one of those conditions that are largely misunderstood, and not much is known about it. This post aims to change that. Scroll down to learn more about this condition, why it happens, how to recognize it, and your treatment options.

What is Myasthenia Gravis

Myasthenia gravis is a condition indicated by muscle weakness due to impaired communication between nerves and muscles. It usually affects muscles in the eyes, face, neck, arms, and legs. The condition can affect your ability to blink, make facial expressions, chew, talk, swallow, raise your arms, or walk.

Although there is no cure for myasthenia gravis, it is possible to manage the symptoms and improve quality of life.

Types of Myasthenia Gravis

Not all cases of myasthenia gravis are the same. Different types of this condition include:

• Autoimmune myasthenia: the most common type of myasthenia gravis and can be further divided into ocular and generalized. Ocular myasthenia involves the weakening of eyes and eyelids and can evolve into a generalized type. Generalized myasthenia affects muscles in the eyes, neck, arms, legs, or throat.
• Neonatal myasthenia: The fetus receives antibodies from the parent with myasthenia gravis.
• Congenital myasthenia: not an autoimmune condition, but a condition with a predominantly genetic component.

How Common is Myasthenia Gravis?

According to the Myasthenia Gravis Foundation of America, the prevalence of this autoimmune condition in the United States is 14 to 20 per 100,000 population. It is estimated that 36,000 to 60,000 people in the U.S. have myasthenia gravis. That said, the prevalence of myasthenia gravis could be higher because the condition is highly misdiagnosed.

While childhood myasthenia gravis is not common in Western countries, it’s quite prevalent in Asia. Around 50% of patients with this condition are younger than 15 years.

Symptoms of Myasthenia Gravis

The primary symptom of myasthenia gravis is muscle weakness, which worsens when the affected muscle is engaged. Muscle weakness comes and goes as symptoms of myasthenia gravis get better with rest. However, symptoms of this autoimmune condition tend to worsen with time. In most cases, myasthenia gravis causes the following symptoms:

• Ptosis (drooping of one or both eyelids)
• Diplopia (double vision) resolves or improves when the eyes are closed
• Slurred speech
• Difficulty making facial expressions
• Difficulty chewing and swallowing
• Quiet or nasal-sounding voice
• Shortness of breath
• Inhaling pieces of food or choking
• Difficulty holding the head up
• Waddling walk
• Aching muscles after they’ve been engaged
• Difficulty performing physical tasks

Causes and Risk Factors of Myasthenia Gravis

Myasthenia gravis occurs when your immune system starts attacking itself. The exact reason that happens is still unclear. Some cells of the immune system in your thymus (a gland beneath the breastbone at the heart level) fail to identify threats to your body. As a result, they may “encourage” the immune system to produce antibodies that block or neutralize muscle receptor sites for neurotransmitter acetylcholine. In turn, muscles start receiving fewer nerve signals.

Moreover, antibodies can block muscle-specific receptor tyrosine kinase (MuSK), which is a protein that participates in the formation of the nerve-muscle junction. Autoimmunity is the most common cause, but not the only one. Mother can pass antibodies to their children in the womb.

The biggest risk factors for myasthenia gravis include:

• Female gender
• Age (around 40 years for women and 60 for men)
• History of other autoimmune conditions e.g., rheumatoid arthritis
• Taking medications for malaria and arrhythmia
• Having undergone surgery
• History of infection

Diagnosis of Myasthenia Gravis

Diagnosis of myasthenia gravis consists of the following:

• Neurological exam: involves checking your muscle tone and strength, reflexes, coordination, balance, and senses of light and touch.
• Ice pack test: This test revolves around placing a bag filled with ice on your eyelid and monitoring improvements.
• Blood test: shows the presence of non-typical antibodies
• Repetitive nerve stimulation: involves attaching electrodes to your skin. Small electricity pulses extend through electrodes to measure if the nerve can send a signal to your muscle.
• Single-fiber electromyography (EMG): evaluates electrical activity traveling between muscle and the brain.
• Imaging tests: the doctor may order a CT or MRI to check for the presence of a tumor on the thymus.

Once the doctor diagnoses myasthenia gravis, they proceed to determine the stage. There are five stages or classifications ranging from Class I, where muscle weakness affects your eye to Class V, where severe disease affects your breathing.

Treatment of Myasthenia Gravis

Symptoms of myasthenia gravis are managed through several approaches, such as:

• Medications: the doctor may prescribe cholinesterase inhibitors to improve communication between nerves and muscles, corticosteroids to act on the immune system so that it’s less able to produce antibodies, and immunosuppressants that change the immune system.
• Intravenous therapy: a short-term approach to manage systems that suddenly worsen or before surgery. Common IV therapies include plasmapheresis to remove antibodies that block transmission of signals from nerves to muscles, intravenous immunoglobulin to provide typical antibodies to improve immune system response, and monoclonal antibody, which is used when other medications don’t work.
• Surgery: patients with a tumor on the thymus may need thymectomy, a procedure to remove this gland.

You can manage symptoms of myasthenia gravis by using electric appliances and power tools, wearing an eye patch, and installing grab bars and railings where you need support in your home. Eat when your muscle strength is good, and chew your food slowly.

Conclusion

While myasthenia gravis isn’t curable, you can manage the symptoms and improve your life on a day-to-day basis. If you’re experiencing the symptoms described above, make sure to see your doctor.