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Myasthenia Gravis

Myasthenia Gravis is a chronic autoimmune condition that leads to weakness in the skeletal muscles. Your skeletal muscles are muscles that attach to your bones and allow body movement. Myasthenia Gravis leads to destruction of the communication between muscles and nerves, which leads to muscle weakness.

Every time you move your muscles there are nerves that send signals to your muscles to contract and relax. With Myasthenia Gravis, these signals are not received because the body attacks the signal’s receptors on the muscle cells. Myasthenia Gravis is an autoimmune condition, which means that your own body is attacking the muscle cell receptors. This can lead to waxing and waning symptoms as your body ramps up production of autoantibodies against the muscle receptors. The indicative sign of myasthenia gravis is muscle weakness that worsens throughout the day, then improves after a period of rest.

Symptoms

The main symptoms of myasthenia gravis include muscle weakness that worsens throughout the day. Specific symptoms include:

  • Weakness of the eye muscles, leading to eyelid droopiness by the end of the day
  • Blurry vision
  • Difficulty swallowing
  • Shortness of breath
  • Difficulty with speech enunciation
  • Weakness in your skeletal muscles

As myasthenia gravis progresses, it can also lead to lung involvement and even respiratory failure.

Causes & Risk Factors

Unlike most autoimmune disorders, myasthenia gravis affects males and females almost equally. It has a slight predominance in younger females under the age of 40, but many men are affected as well.

There is no known trigger that causes myasthenia gravis to start, but doctors do know which part of the nervous system is affected. When myasthenia gravis occurs, your body forms antibodies that block or destroy the receptors for neurotransmitter chemicals at the level of the muscle. This leads to poor muscle contractions and can prevent your muscles from contracting. Fortunately, since doctors have determined the cause of the muscle weakness, it can be treated.

Diagnosis

To confirm the diagnosis of myasthenia gravis, a doctor may run a variety of tests including:

  • Physical exam with thorough neurologic exam.
  • Blood tests to look at specific antibody levels that are elevated in the disease process.
  • Edrophonium test – Edrophonium is a drug that can block the breakdown of a specific neurotransmitter that leads to muscle contraction. By blocking its breakdown, patients with myasthenia gravis who are injected with Edrophonium can regain muscle function and their weakness improves. This test is the gold standard for diagnosis.
  • Nerve stimulation tests — by stimulating the nerves that contract muscles repeatedly, doctors can determine if your muscles are weaker than normal.

Treatment

Once the diagnosis of myasthenia gravis has been made, your doctor may offer you a variety of treatments to help improve the quality of your life. Immunosuppressant medications, medications that increase neurotransmitters, and intravenous immunoglobulin can all be utilised to help decrease degradation of neurotransmitters and increase muscle strength.

Myasthenia gravis is a rare condition that leads to muscle weakness that worsens throughout the day. It can be difficult to diagnose due to its nonspecific symptoms, but once diagnosed there are multiple treatment options available.

 
 
 

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