It is a health condition that negatively affects the communication between nerves and muscles. Thus, muscle weakness that commonly worsens during the day and with activity occurs. The first symptoms are drooping eyelids and double vision. In addition, if you experience this disease it may become problematic to lift objects, swallow, and even speak. While it is a lifelong condition, there are different treatment options that can help lessen the symptoms.
What is Myasthenia Gravis?
An autoimmune condition that provokes skeletal muscle weakness is called myasthenia gravis (MG). Skeletal muscle means those that connect bones with muscles, which help to move. Commonly, MG impacts the eyes, neck, face, arms, and legs muscles. However, it also may negatively affect the ability to:
- Blink or move the eyes
- Keep open the eyes
- Make facial expressions
- Raise your arms up
- Walk upstairs and get up from a chair
- Swallow, chew, and talk
Weakness of the muscles worsens after activity and improves after rest. Unfortunately, it is not a curable condition but a suitable treatment can improve the symptoms and your quality of life.
Myasthenia Gravis Types
- Congenital Myasthenia – This type of MG is caused by a genetic change, which means that it is not an autoimmune condition.
- Neonatal Myasthenia – An infant can have a sucking reflex or weak cry at birth from the birthing parent. However, it is caused by certain antibodies from the birthing parent with myasthenia gravis. Anyway, these symptoms go away within 3 months.
- Autoimmune Myasthenia – It is the most common type of MG and it is not known well the exact cause. However, it is considered that the production of some types of antibodies (immune system proteins) provokes this condition.
Check below some subtypes of an autoimmune myasthenia:
- Generalized – In such cases, weakness of the muscles occurs mostly in your eyes, neck, arms, legs, and throat. That’s why it is difficult to swallow, talk, walk, or climb stairs.
- Ocular – People with this type of autoimmune myasthenia experience weakness in the muscles that move the eyes and eyelids. Furthermore, ocular myasthenia gravis may evolve into a generalized over time.
Symptoms
Usually, the symptoms may be different among people because are based on the severity of the condition, other existing health conditions, your age, weight, and others. For example:
- Weakness of the muscles in the neck, arms, legs, throat, face, and fingers
- Fatigue
- Droopy eyelids (ptosis)
- Blurred or double vision
- Limited facial expressions
- Speaking, swallowing, or chewing problems
- Walking problems
In most cases, the first MG symptoms appear suddenly. Moreover, rarely, MG impacts the muscles in your respiratory system. Hence, it may lead to shortness of breath or even to other serious respiratory problems. In case you notice any of the previous symptoms, immediately contact your healthcare professional.
Causes
An autoimmune myasthenia usually appears due to the immune system. It mistakenly attacks itself and it is not known the exact cause of why it happens. It is thought to occur because your body’s defense cannot identify what is a threat (viruses or bacteria) and healthy cells.
How Does MG Affect the Body?
In case the immune system works properly, muscles and nerves work together. For example:
- In normal circumstances, nerves send signals to the muscles across a synapse. This process is called neuromuscular junction. Therefore, nerves release acetylcholine (a special molecule needed for communication between nerves and muscles).
- This molecule binds the acetylcholine receptors located on the site of the muscle.
- As a result, acetylcholine triggers muscle fibers to contract.
- However, if you have MG, some antibodies destroy the receptor sites, which block nerve-muscle communication.
Is MG inherited?
You can inherit an autoimmune myasthenia in very rare cases. Usually, congenital and neonatal myasthenia are inherited conditions.
Risk Factors
This condition commonly occurs in women around their 40s and men around their 60s. However, MG can negatively affect anyone at any age. Check below some risk factors:
- Family history of autoimmune diseases (including rheumatoid arthritis, lupus, and others)
- Thyroid disease
In some cases, you may have MG, and symptoms begin when you:
- Use medicines for malaria or arrhythmia
- Underwent surgery
- Experience an infection
Complications
Stress and depression may happen due to the inability to participate in activities and enjoy. Some research showed that people with MG can tolerate light activities (such as casual walking, lightweight training, slow dancing, and others).
In addition, roughly 1 in 5 people with MG experience a myasthenic crisis or severe respiratory muscle weakness. In such cases, a respirator or other treatments may needed. Furthermore, about 20% of people with myasthenia gravis will experience at least one myasthenic crisis during their entire life.
Those who experience MG may have thymus gland conditions that commonly provoke symptoms. The thymus is a small organ located in the upper chest and it is a part of the lymphatic system. This organ produces white blood cells that help fight against infections. However, about 60-70% of people with MG have overactive thymic cells and approximately 1 in 10 people have thymus gland tumors (thymomas), which can be noncancerous or cancerous.
Diagnosis
Healthcare providers usually diagnose myasthenia gravis by performing a physical examination, asking questions about symptoms, and medical and family history. Check below some tests that can confirm whether you have MG or not:
- Electromyography (EMG) – This helps to measure the electrical activity of the muscles and nerves, which can determine if there are communication problems between them.
- Imaging Scans – These procedures are done to identify any thymus gland problems (such as tumors). Physicians usually perform MRI and CT scans.
- Blood Antibody Tests – Roughly 85% of people with MG have abnormally increased levels of acetylcholine receptor antibodies in the blood.
Treatment
Unfortunately, there is no cure for this health condition. However, treatments may lessen the symptoms and improve your quality of life. Examples include:
- Medicines – Usually, used to decrease symptoms.
- Monoclonal Antibodies – These involve intravenous or subcutaneous infusions of biologically engineered proteins that help to suppress an overactive immune system.
- Plasma Exchange (Plasmapheresis) – During this procedure you are connected to a machine that helps to remove antibodies from the blood plasma. It also replaces them with plasma solution or donor plasma.
- Intravenous or Subcutaneous Immunoglobulin (IVIG or SCIG) – Infusions of donor antibodies are given to the patient for 2-5 days. These procedures help to lessen myasthenic crisis and generalized MG.
- Surgery – In some cases, a removal of the thymus gland may be required. This surgery is called thymectomy.
MG Medicines
Check below the common drugs prescribed by doctors for MG treatment:
- Immunosuppressant Medicines – Physicians prescribe corticosteroids that help to lessen the inflammation. They also may help to reduce the production of abnormal antibodies.
- Cholinesterase Inhibitors (Anticholinesterase) – These medicines help to boost signals between muscles and nerves. This effect helps to improve muscle strength.
Consult with your doctor before using any medication.
Frequently Asked Questions
How common is myasthenia gravis?
About 60,000 people suffer from MG in the U.S. Moreover, approximately 20 people out of every 100,000 people suffer from MG in the entire world.
What are myasthenia gravis stages?
- I – Weakness of the muscles impacts the eyes only.
- II – Mild muscle weakness.
- III – Moderate weakness of the muscles.
- IV – Severe muscle weakness.
- V – Severe muscle weakness that affects your respiratory system and you may need intubation or mechanical ventilation.
Ask your doctor if you have any questions.
What is the life expectancy of a person with myasthenia gravis?
Commonly, people with this condition have a normal life expectancy. However, some life-threatening results may appear during a myasthenic crisis.
