Myasthenia Gravis: Symptoms, Causes, Diagnosis, Treatment, Complications, Outlook

Medically Reviewed by Dr. K on 21 April 2021

Table of Contents :

  1. Myasthenia Gravis
  2. Symptoms
  3. Causes
  4. Diagnosis
  5. Treatment 
  6. Complications
  7. Outlook

Myasthenia Gravis

 

Myasthenia gravis is a debilitating disease that allows muscles to quickly fatigue and weaken. If you have myasthenia gravis, for example, you can find that your jaw muscles get sore and sluggish after a meal, making it difficult to chew food. After a short period of rest, your muscles can become stronger, enabling you to resume feeding. 

 

This condition is characterised by a waxing and waning weakening in muscles that worsens with usage and improves with rest. There are times that you can experience further symptoms (referred to as an exacerbation) and times when symptoms decline or vanish (remission). 

 

Generalized myasthenia gravis is a form of myasthenia gravis that affects various muscle groups in the body. Other typical muscle groups that are impaired can find chewing, swallowing, smiling, shrugging, lifting your arm up, gripping, rising to a stand, or walking up stairs difficult. A patient is said to be in myasthenic crisis when the muscles used for breathing are impaired. This is a potentially fatal condition. 

Myasthenia gravis may affect anybody, although it is more common in women between the ages of 20 and 40 and men between the ages of 50 and 70. Because of antibodies transmitted from the mother's bloodstream, a baby born to a woman with myasthenia gravis may experience transient and possibly life-threatening muscle weakening (neonatal myasthenia). Typically, antibodies are removed from the baby's bloodstream within the first few weeks of life, and the baby gains natural muscle tone and strength.

Symptoms

 

The disease commonly affects the muscles that regulate eye and eyelid function, so eyelid drooping and/or distorted or doubled vision might be the first symptoms you experience. In one to two years, patients will eventually develop deficiency in other muscle classes. 

 

The following are some of the more common signs of myasthenia gravis:

  • Weakness in your eye muscles
  • Drooping eyelids
  • Double vision
  • Blurred vision
  • Change in your facial expression
  • Trouble swallowing
  • Shortness of breath
  • Problems speaking
  • Problems walking and lifting things
  • Trouble holding up your head

A myasthenic crisis occurs when the muscles that regulate the breathing become too weak to control. This is a medical emergency that necessitates the use of a ventilator to assist you in breathing. At least one myasthenic crisis affects between 15% to 20% of individuals with myasthenia gravis. A virus, fatigue, surgery, or a drug reaction may all trigger a myasthenic crisis.

 

Causes

 

Nerves direct the muscles to function under regular circumstances by passing a message via a receptor. Acetylcholine is the chemical that transmits this message. Your muscle learns to contract as acetylcholine attaches to a nerve receptor. The acetylcholine receptors in your body are attacked in myasthenia gravis. 

 

Myasthenia gravis is classified as an inflammatory condition. In an autoimmune disorder, the body's antibodies (special proteins in your body that are meant to combat foreign attackers including microbes, viruses, or fungi) misinterpret a portion of your own body for a foreign invader, causing it to be destroyed. Antibodies obstruct, strike, or damage the acetylcholine receptors needed for muscle contraction in myasthenia gravis. 

 

Nobody understands what triggers the body's production of antibodies that attack acetylcholine receptors. The thymus gland, which aids in the production of antibodies, seems to be involved in certain instances. 

 

A thymoma, a tumor of the thymus, is present in around 15% of all myasthenia gravis patients. Despite the fact that most thymomas are benign (noncancerous), the thymus is normally cut (thymectomy) to avoid cancer from spreading. In reality, even though no tumor is present, thymectomy seems to enhance symptoms of myasthenia gravis in certain cases.

 

Diagnosis

 

Your doctor will do a neurological examination to see whether you have myasthenia gravis. This consists of a test of your:

  • Reflexes
  • Muscle strength
  • Muscle tone
  • Touch
  • Sight
  • Coordination
  • Balance

Then you'll have scans that examine the effects of myasthenia gravis in more detail. These are some of them:

  • Edrophonium test. A chemical named edrophonium chloride is injected into you by the doctor to see how it increases your muscle function. If it does show improvement, you might be suffering from myasthenia gravis.
  • Ice pack test. If you have a drooping eyelid, your doctor can apply an ice pack to it for two minutes to see whether the cold will help.
  • Blood test. A sample of the blood will be drawn and sent to a lab to be tested for antibodies that damage muscle nerve receptors.
  • Repetitive nerve stimulation. This test sends short electrical waves into your muscles to see how your nerves respond to the signals.
  • Single-fiber electromyography (EMG). A doctor inserts a thin wire electrode through a muscle through your tissue. It will measure the electrical activity in the muscles and brain.
  • Imaging. A CT scan or an MRI might be recommended by your doctor to check for a tumour on your thymus that is causing symptoms.
  • Pulmonary functioning tests. Your doctor will examine your breathing and determine if myasthenia gravis has damaged your lungs.

Treatments

 

Your treatment would be determined by the age, the severity of your symptoms, and the rate at which your illness is improving. It's possible that you'll require a combination of medications. Your doctor can prescribe one of the following medications:

  • Cholinesterase inhibitors:mThese drugs help the nerves and muscles communicate more effectively. They will assist with muscle strengthening.

  • Corticosteroids: Prednisone and other corticosteroids suppress the immune system and delay the production of antibodies that could be blocking the nerve receptors.

  • Immunosuppressants: To help minimize your immune system reaction, your doctor can add immunosuppressants to your corticosteroids.

Your doctor may prescribe intravenous (IV) medication if you're experiencing a sudden worsening of symptoms or will be undergoing surgery or other treatments soon. There are a variety of options for this:

  • Plasmapheresis: Since it filters the blood, this treatment is similar to dialysis. Certain antibodies are removed from the blood by a pump. This medication is usually only effective for a few weeks until the results begin to fade.
  • Intravenous immunoglobulin (IVIg): This treatment involves the injection of fresh antibodies into the bloodstream. These antibodies assist with symptoms by altering the immune system's reaction. The effects usually last 3-6 weeks.
  • Monoclonal antibodies. If other therapies have failed, your doctor would most likely prescribe this alternative. They have the potential to cause severe side effects.

If your myasthenia gravis is caused by a tumor on your thymus gland, surgery to extract the whole gland might be needed (thymectomy). Even if you don't have a tumor, removing your thymus gland can make you feel better. The results of a thymectomy can take years to manifest.

 

Your thymus can need open surgery to be removed. A surgeon will cut open your breastbone to access your thymus and remove it. 

 

Minimally invasive surgery is another option that might be helpful. There are two options:

  • Video-assisted thymectomy: Surgeons remove the thymus gland by tiny cuts in your neck or stomach, using an endoscope, a large, slender camera, and tools.
  • Robot-assisted thymectomy: Surgeons use a device with a monitor and mechanical arms to remove the thymus by making the same minor cuts as with video-assisted thymectomy.

Lifestyle modifications can be attempted to relieve the symptoms of myasthenia gravis, such as:

  • When you eat, conserve your energy. If chewing is difficult for you, eat while you have the most energy. You might find it simpler to consume many small meals during the day rather than larger ones less frequently. Try to consume soft foods and take a few smaller bites at a time.
  • Install safety equipment. Place handrails by the bathroom or near chairs, or somewhere else that you may like a helping hand. Remove any tripping hazards, such as rugs or litter on the concrete. Create a safe environment for yourself at home to make your life easier.
  • Utilize technology. Use an electric toothbrush and can opener, or some other gadget that allows you to conserve your energy.
  • Wear an eye patch over your eye. It may aid in the reduction of double vision. When watching TV or reading, choose one and switch the eye patch between both your eyes from time to time.
  • Make preparations ahead of time. Use your energy wisely. Complete tasks or errands while you're at your most energetic. 

Complications 

 

Myasthenic crisis is one of the most severe potential complications of MG. This is characterized by life-threatening muscular fatigue, which may involve breathing difficulties. Discuss the risks with your doctor. If you have difficulty breathing or swallowing, dial 911 or go to your nearest emergency department immediately.

 

People with MG are more likely to develop other inflammatory diseases like lupus and rheumatoid arthritis.

 

Outlook

A number of factors influence MG's long-term outlook. Some individuals will only experience minor signs and symptoms. Others will be required to use a wheelchair in the future. Discuss with your doctor what you should do to reduce the severity of the MG. Many patients can have their disease progression slowed down if they receive proper treatment early on.

Sources

Referenced on  10.4.2021

  1. Section of Behavior Medicine at the Children's Hospital at The Cleveland Clinic.
  2. Walker and M.C. Roberts (Eds.) The Handbook of Clinical Child Psychology (3rd Ed., 2001). New York: NY: John Wiley & Sons.
  3. Goldenberg WD. (2016). Emergent management of myasthenia gravis.
    emedicine.medscape.com/article/793136-overview
  4. Howard JF. (2015). Clinical overview of MG.
    myasthenia.org/HealthProfessionals/ClinicalOverviewofMG.aspx
  5. Mayo Clinic Staff. (2017). Myasthenia gravis.
    mayoclinic.org/diseases-conditions/myasthenia-gravis/symptoms-causes/syc-20352036
  6. Myasthenia gravis. (2018).
    ghr.nlm.nih.gov/condition/myasthenia-gravis
  7. Myasthenia gravis. (n.d.).
    mda.org/disease/myasthenia-gravis
  8. Myasthenia gravis. (n.d.).
    ncbi.nlm.nih.gov/pubmedhealth/PMHT0024823/
  9. Myasthenia gravis: Causes/inheritance (n.d.).
    mda.org/disease/myasthenia-gravis/causes-inheritance
  10. Myasthenia gravis [Fact sheet.] (2017).
    ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Myasthenia-Gravis-Fact-Sheet
  11. Pyridostigmine. (n.d.).
    ncbi.nlm.nih.gov/pubmedhealth/PMHT0011896/
  12. Treatment for MG. (2015).
    myasthenia.org/WhatisMG/TreatmentforMG.aspx
  13. https://www.webmd.com/brain/understanding-myasthenia-gravis-basics  
  14. https://www.healthline.com/health/myasthenia-gravis#outlook

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