Myasthenia gravis is a condition that causes the muscles to weaken easily. The cause of this condition is the disruption of the communication that takes place between muscles and the nerves. As of now, there isn’t any cure for myasthenia gravis yet, but treatment can help relieve the signs and symptoms.
What is myasthenia gravis?
Myasthenia gravis can be defined as a medical condition that makes your muscles weak and tired easily. For instance, if you have myasthenia gravis, you may notice your jaw muscles getting tired and weak while you are in the middle of your meal. It may make it difficult for you to chew food properly. Once you have rested for a while, the muscles may get stronger again, and you can eat again. This weakening of the muscles – improving with rest and worsening with use – is the common sign of myasthenia gravis.
If you suffer from myasthenia gravis, you may notice times when your symptoms get worse – known as an exacerbation. Other times, your symptoms may reduce or disappear – known as remission.
Myasthenia gravis can affect people of any age group. But younger women below the age of 40 and men older than 60 years are more prone to developing it.
What are the noticeable symptoms of myasthenia gravis?
Myasthenia gravis worsens over time, as the weakened muscle is used frequently. Since the muscle usually improves with rest, the weakness may come and go.
Myasthenia gravis can affect any muscle you control voluntarily in your body, but some parts of the muscles are more affected than others.
- Eye muscle
In almost 50 percent of the myasthenia gravis cases, the first signs and symptoms are observed in the eye muscle. The symptoms include:
- Ptosis – Drooping of one or both eyeballs.
- Diplopia – Double vision. This may occur horizontal or vertical and often improves when one eye is closed.
- Face and throat muscle
In about 15 percent of the cases, the first symptoms develop around the face and throat muscle. The symptoms include:
- Impaired speaking – Depending on the muscle affected, your speech may sound different.
- Difficulty chewing and swallowing – Myasthenia gravis may cause you to choke, or make drinking or eating difficult. In some cases, the liquids you try to swallow may come out of your nose.
- Changed facial expressions – This may cause your facial expressions to look different.
If you notice any of these symptoms, consult a doctor immediately.
Request an appointment at Apollo Hospitals
Call 1860-500-1066 to book an appointment
What are the causes of myasthenia gravis?
The causes of myasthenia gravis are:
Your nerves release chemicals known as neurotransmitters that communicate with the muscles. The muscles have receptor sites that receive the neurotransmitters.
When you develop myasthenia gravis, the immune system starts producing antibodies that destroy these receptor sites at the muscles for a neurotransmitter known as acetylcholine. With a fewer number of receptor sites, the muscles receive fewer signals. This results in the weakness of the muscles and causes myasthenia gravis.
The antibodies released by the immune systems can also result in the blockage of a protein known as tyrosine kinase. It is essential in forming the nerve-muscular junction.
- Thymus gland
The thymus gland is located in your upper chest behind the breast bone and is a part of the immune system. The gland is known to maintain the production of the antibodies that destroy acetylcholine.
In healthy adults, the thymus gland is small in size. But in people suffering from myasthenia gravis, the gland is abnormally large.
- Other causes
In some cases, antibodies blocking acetylcholine or the thymus gland aren’t the causes. Such people have antibody-negative myasthenia gravis. Here, the antibodies destroy another type of protein known as lipoprotein-related protein 4.
In rare cases, pregnant women with myasthenia gravis give birth to babies with myasthenia gravis. If treated early, the condition goes away within two months.
What are the complications of myasthenia gravis?
A majority of the complications of myasthenia gravis are treatable, but some can be severe.
- Myasthenic crisis
It is a life-threatening condition that develops when the muscles that control the breathing become weak. To provide medical help with breathing, emergency treatment may be needed. Blood-filtering therapies and medications are given to help with breathing.
- Thymus gland tumors
In some cases, people with myasthenia gravis develop tumors in the thymus gland. The tumor is called thymomas and is usually non-cancerous.
- Autoimmune disorders
Some people with myasthenia gravis develop other autoimmune conditions such as lupus or rheumatoid arthritis.
What are the tests done to diagnose myasthenia gravis?
After reviewing your symptoms and medical history, the doctor will do a physical examination. The tests conducted for the diagnosis include:
- Neurological examination
The doctor will examine your neurological health by testing your muscle tone, sense of touch, reflexes, coordination, muscle strength, and balance.
- Edrophonium test
A chemical called edrophonium chloride will be injected into your muscles. This will temporarily improve the muscle strength, helping the doctors find out if you have myasthenia gravis.
The chemical helps block the enzyme that breaks down acetylcholine – a neurotransmitter that transmits signals from the nerve endings to muscle receptor sites.
- Blood test
A blood test will be conducted to check for the presence of the abnormal antibodies that destroy the muscle receptor sites.
- Repetitive nerve stimulation
For this nerve conduction study, the doctors will attach electrodes to your skin where the muscles have weakened. Small pulses of electricity will be sent through the electrodes to check how well the nerve can send signals to the muscle.
To confirm the diagnosis of myasthenia gravis, the doctors will test the nerve repeatedly to check if it worsens with fatigue.
- Single-fiber electromyography (EMG)
This test is conducted to check the electrical activity traveling between your brain and muscle. Your doctor will insert a fine wire electrode to your muscle to check for a single muscle fiber.
- Pulmonary function tests
These tests are conducted to check if myasthenia gravis has affected your breathing.
- CT or MRI may be done to check the thymus gland as well.
What are treatment options available for myasthenia gravis?
Depending on the severity of myasthenia gravis, how fast it is progressing, your age, and symptoms, the doctor will plan a treatment plan for you. The treatment options include:
Your doctor may give you medicines like neostigmine or pyridostigmine to improve the connection between your nerves or muscles. These medicines will not provide a permanent solution but can improve muscle strength and muscle contraction.
Few of the side effects of this medication include diarrhea, sweating, gastrointestinal upset, nausea, and excessive salivation.
Corticosteroids such as prednisone help with inhibiting the immune system and limit the production of abnormal antibodies.
But, prolonged use of corticosteroids can lead to severe side effects such as diabetes, weight gain, bone thinning, and increased risk of infections.
Medications such as mycophenolate mofetil, methotrexate, azathioprine, tacrolimus, and cyclosporine will help alter your immune system. These medications may take months to work and sometimes are prescribed with corticosteroids.
Some serious side effects of immunosuppressants are kidney or liver damage and increased risk of infections.
This therapy is similar to dialysis. The antibodies will be removed from your blood by routing it through a machine. However, this therapy helps only for a few weeks. Repeated procedures can lead to serious problems such as difficulty in assessing veins during the treatment.
This therapy will provide normal antibodies to your body, to alter the immune system response. The benefits are visible in a week and can last up to three to six weeks.
This treatment is prescribed to patients who don’t respond to other treatments. Intravenous medications such as eculizumab and rituximab are used in this treatment.
In some cases, people with myasthenia gravis have thymoma – a tumor in the thymus gland. The doctor will then remove the gland.
Even if you don’t have a thymoma, removal of the gland can help improve your myasthenia gravis symptoms. But the benefits of this surgery can take years to develop.
Frequently Asked Questions (FAQs)
- What can trigger myasthenia gravis?
Some of the factors that can trigger myasthenia gravis include:
- Menstrual periods
- Medications such as quinidine gluconate, quinine, quinidine sulfate, or beta-blockers
- Is exercise good for myasthenia gravis?
Exercises with a low impact such as swimming, walking, or light jogging are harmless and may help reduce fatigue.
- Why is myasthenia gravis called the snowflake disease?
Myasthenia gravis is often called the snowflake disease as the amount and location of the muscle affected vary in every patient.
Request an appointment at Apollo Hospitals
Call 1860-500-1066 to book an appointment