Myasthenia Gravis: All you need to know about Muscle Weakness & Fatigue
Myasthenia gravis is distinguished by weakness and fatigue of the muscles that are in your voluntary control. Myasthenia gravis is caused by a breakdown and crash in the communication between nerves and muscles and there no cure is provided for the myasthenia gravis but the further treatment help to relieve the sign and symptoms of myasthenia gravis (included weakness of arm, muscle, and legs, the problem of double vision, drooping eyelids, and speech difficulty issues) because it frequently affect the muscle that helps to control the movement of the eye, facial expression, swallowing, and speaking. Myasthenia gravis affects an individual of any age, but mostly it is found in women under the age of 40 and men over the age of 60.
Pathophysiology of Myasthenia Gravis:
Myasthenia gravis is a rare, autoimmune disease that is caused by antibodies-mediated barriers of neuromuscular transmission that appear as a weakness of the skeletal muscle.
The attack of autoimmune occurs when auto-antibodies (produces by person immune system) form against the nicotinic acetylcholine receptors (nAChR is a primary receptor in your muscles for communication of nerve and muscles for controlling the muscles contraction) at the neuromuscular junction of the skeletal muscles. Even though the main target of the autoimmune attack the skeletal muscles (nAChR), while the other antigens target the neuromuscular junction that is also implicated.
The neuromuscular junction is caused by antibodies that target the components of postsynaptic membrane (the membrane that receives the signals), weaken neuromuscular transmission, and also cause the weakness and fatigue of muscles and it can be localized the certain type of muscles group, with the involvement of medulla oblongata, and it can become life-threatening.
The pathological process of myasthenia gravis depends on the target of autoantibodies. Mostly the myasthenia gravis is also caused by immunoglobulin igG1 and igG3 antibodies and they develop complement-mediated destructions with increasing AChr rate.
However, the thymus gland is also involved in many of the patients of myasthenia gravis because of genetic approaches which mostly fail to understand the tolerance of the immune system.
What are the symptoms of Myasthenia Gravis?
As we know, weakness of muscles is usually caused by myasthenia gravis and it worsens as, whenever the affected muscle is used. The weakness of muscles might come and go with the passage of time and the symptoms of myasthenia gravis tend to progress over some time. It becomes worse within a few years after the diagnosis of myasthenia gravis. The symptoms appear certain of muscles that affected than others and these are,
1. Muscles of face and throat:
The people with myasthenia gravis, firstly symptoms involve muscles of the face and throat, it includes,
i. Inability of Speaking: In myasthenia gravis, you might face inability or impair speaking and your voice becomes soft or nasal (it depends on which muscles of speaking have been affected.
ii. Difficulty in swallowing: You might gag and choke easily and face difficulty to eat, drink or take pills, while in some cases, whenever you drink and try to swallow the liquid, mostly it comes out of your nose.
iii. Difficulty in chewing: The people with myasthenia gravis also faced difficulty in chewing and they faced hard to chew (such as beefsteak).
2. Change facial expressions:
The expression of your face also changed due to myasthenia gravis (such as whenever you smile, your face expression gets changed).
3. Muscles of Eye:
About 40-45% of people with myasthenia gravis, having signs and symptoms of eye movement problems, such as
i. Ptosis- Falling or dropping of one or both eyelids and movement of the eye become worse due to tiredness of muscles and it is also named as Blepharoptosis.
ii. Diplopia- Simultaneously, people with myasthenia gravis have a double vision with the perception of double or blurry vision. (might be horizontal or vertical).
4. Muscles of Neck and Limb:
The people with myasthenia gravis also faced weakness of the neck, arm, and limb muscles and it affected the pattern of your walk.
5. Shortness of breath:
About 15% of people with myasthenia gravis also face the symptom of shortness of breath.
Causes of Myasthenia Gravis:
The thymus gland is the small organ of your body behind your breastbone and it plays a vital role in the immune system. According to researchers, thymus glands maintain the production of antibodies and it also triggers the antibodies that block the acetylcholine. The people with myasthenia gravis have large abnormally and some people also have thymomas (tumor of the thymus gland), but mostly they are not malignant.
The nerves communicate with muscles by releasing the chemicals and it fits into the receptor sites on your muscle cells at the junction of nerve-muscular. People with myasthenia gravis the immune system produces the antibodies that destroy or diminish your muscles and strength of muscles and your muscles are weak and fatigued because antibodies block the function of your muscles movement.
- It is also caused by the inadequacy in the transmission of your nerve impulses to the muscles.
- People with myasthenia gravis are not always caused by blockage of antibodies and this type of myasthenia gravis is also known as antibodies negative myasthenia gravis.
- Often the mothers with myasthenia gravis have the baby with this disease and it is known as neonatal myasthenia gravis. If the diagnosis was done appropriately, then the recovery of children was done within two-three months.
- Rarely the children who are born with myasthenia gravis are known as congenital myasthenia gravis.
What is the diagnosis of Myasthenia gravis?
- Frequently myasthenia gravis can be more difficult to diagnosed and the physician needs to perform several types of tests to diagnosed appropriately, the diagnosis is based on your past or present medical history with appearing sign and symptoms and your doctor also think and ask you about any problems of the brain which help to diagnose myasthenia gravis. Your physician properly reviews your symptoms and conduct a physical examination. It may includes
- Neurological examination- Your doctor appropriately checks your neurological health issues by testing the reflexes, strength of your muscles, muscle tone, coordination, balance, and senses of touch.
- The tests that help the doctor to confirm the diagnosis of myasthenia gravis include,
i. Blood test- To evaluate myasthenia gravis your doctor prescribes your blood test to diagnose the myasthenia gravis and look at the antibodies that inhibit the signals between your nerves and the muscles because elevated levels of antibodies usually cause the myasthenia gravis.
ii. Nerve Tests- If the test of your blood is normal, but your doctor is still confused to reach the diagnosis of myasthenia gravis, then they suggested never test to evaluate your brain function properly. Nerves test also named as electromyography that involves the insertion of a small needle into the muscles to measure the electrical activity and these small needles are inserted around your eyes or possibly in the arms.
iii. Edrophonium test- After performing the blood test and nerve test your doctor still confused about your diagnosis than they suggest edrophonium test that involves an injection which is named as edrophonium chloride (block the enzyme that breaks the acetylcholine) and your doctor also see the improvement of your muscles strength after injected the injection, it’s mean you must have diagnosed with myasthenia gravis. This test is done rarely because of the risk and side effects of this test that might lower your heartbeat and face difficulty in breathing.
iv. Ice pack test- If you are facing the problem of drooping eyelids, then your doctor performs the ice pack test by putting this ice pack on your eyelids, while after a few minutes your doctor removes the bags of ice on your eyes and then analyzes the drooping of the eyelid.
v. Single-fiber electromyography (EMG)– This test helps to visualize the electrical activity of your brain and muscles. In this test, your doctor inserts fine wire through your skin into the muscles for testing the muscle fiber.
vi. Imaging- CT scan or MRI is also performing to evaluate the growth of your tumor and any abnormalities in your thymus glands.
vii. Pulmonary function tests- This test is performed to see the pattern of patients breathing, that the patient is having any difficulties in the breath.
How do you treat myasthenia gravis?
There are various types of treatments available for myasthenia gravis that would be done alone or in combination and it helps to relieve the signs and symptoms of myasthenia gravis. The treatment of myasthenia gravis depends on the patient’s age, and its severity (how it progresses on your body). The treatment includes medication, surgery, and intravenous therapies.
i. Corticosteroids- Corticosteroids are that type of medication that is called as immunosuppressant and it helps to reduce the production of your antibodies- The corticosteroids such as prednisone inhibit the immune system and restrict the production of your antibody but extend the use of corticosteroids, may lead the severe type of side effects (such as weight gaining, diabetes, risk of infections).
ii. Cholinesterase inhibitors- Cholinesterase inhibitors are that type of chemicals that help to prevent the breakdown of the neurotransmitter (acetylcholine). The cholinesterase inhibitors such as pyridostigmine and neostigmine might increase the communication between your nerves and muscles. These inhibitors do not cure the myasthenia gravis, but it helps to enhance the contraction of your muscles and strengthen it.
The possible side effects of cholinesterase inhibitors include gastrointestinal upset, diarrhea, nausea, excessive salivation, and sweating.
iii. Immunosuppressants- These are the medications that suppress the strength of your immune system. These are also known as anti-rejection drugs and your doctor recommended this drug (such as azathioprine, cyclosporine, and tacrolimus) to alter your immune system. But prolonged use of this immunosuppressant medication increases the risk of the damages of kidney, and infections.
- As we know people with myasthenia gravis have a thymus gland tumor which is named as thymoma. Your doctor suggested surgery to remove this tumor growth in the thymus gland, which is named as thymectomy. Although the people with myasthenia gravis have no tumor or tumor growth in the thymus gland, the doctor also suggests surgery to remove your glands because thymectomy proves beneficial to treat myasthenia gravis. The thymectomy is an invasive procedure or open type of surgery in which the surgeon split the sternum (central breastbone) and open your chest to remove the thymus gland
- The invasive surgeries that are used to remove gland of the thymus are a smaller type of incision and it might be involved,
i. Video-assisted thymectomy- This is the most important treatment of myasthenia gravis with minimal postoperative pain. In this type of surgery, the surgeon makes a smaller incision in the neck and also in your side of your chest, then uses a long and thin camera to visualize and remove the thymus gland.
ii. Robot-assisted thymectomy- Robotic thymectomy is a surgical procedure to treat the myasthenia gravis and thymic tumors. In this type of surgery, the surgeon makes a small incision inside of your chest to remove the gland by using the robotic system.
- Video-assisted thymectomy and robotic thymectomy are the surgical procedures with less pain, less amount of blood, reduced mortality rates, and short duration of hospital stays.
3. Intravenous therapy:
Intravenous therapy is used as a short term treatment to treat worsening symptoms of diseases, this may include
i. Plasmapheresis- This intravenous procedure separated the plasma and liquid portion of the blood from blood cells. This is a filtering process just as similar to dialysis in which blood is removed by the IV line and it goes through a machine to replace the plasma and it may remove the antibodies to block the transmission of the signals. The risk factor of this intravenous therapy is a sudden drop in blood pressure, bleeding, rhythm problems, and cramps of the muscles. It also might cause an allergic reaction in the body to replace plasma.
ii. Intravenous immunoglobulin (IVIg)- In normal mechanism, your body produces antibodies to fight against the injections but is your immune system not work properly and you are immune-deficient than your body doesn’t make antibodies so this intravenous therapy introduced because this therapy helps your body to produce antibodies which boost your immune system to fight against the germs. The risk factor or side effect or this intravenous therapy includes headache, retention of fluid, and dizziness.
iii. Monoclonal antibody- This type of intravenous therapy used the monoclonal antibodies to bind the cells or proteins. The intravenous medication for monoclonal antibodies is Rituxan that is used to treat the myasthenia gravis and this therapy has a serious type of side effect.
Is exercise good for myasthenia gravis?
According to recent studies, researches showed that the continuous use of muscles weakens your muscles badly because of constantly working and these muscle movements play a vital role to maintain the daily function of the eyes, lungs, and mouth. Previous studies believes that the choice of exercise is the poor choice for myasthenia gravis because of repeated use of muscles, but recent studies suggest that structured exercise enhances aerobic exercise capacity and also strengthens the muscles. Exercise is an important key factor to keep your bones strong and it also helps to maintain mobility. Exercise with the low impact such as walking, jogging, and swimming generally decreases the level of fatigue s in people with myasthenia gravis that’s why the strategy of keeping your body active maintain the function of your muscles
Good To Know:
Myasthenia gravis is a chronic neuromuscular disease that appears as a degree of weakness of muscles of the body in which the thymus gland is affected and triggers your autoimmune system. The cure for this disorder is not availed, but the varieties of treatment should reduce the signs and symptoms of the diseases. To keep your muscles strong, you should do exercise daily because of this regular exercise. You may also save yourself away from the joints or bones problems.
A student of Respiratory Therapist from Dow university of health sciences. She trying to find scientific knowledge and theory to practical problems Related to respiratory care modalities including oxygen and aerosol therapy ,breathing problems and humidity And focusing cardiopulmonary diseases .just to help students to understand in easier way and for acknowledging common people.