Myasthenia Gravis – Myasthenia Gravis is a neuromuscular autoimmune disease in which the immune system mistakenly attacks the communication between the nerves and muscles. This results in the weakening of the skeletal muscles which is responsible for breathing and moving parts of the body, including the arms and legs.
Why is Myasthenia Gravis called an Autoimmune Disease?
Myasthenia gravis comes from a Latin and Greek organ the means muscle weakness. Myasthenia gravis gets worse after period of activity and can improve after rest. Certain muscles such as those that control eye and eyelid movement, facial expression, chewing, talking and swallowing are often (but not always) involved in the disorder. The muscles that control breathing, and neck and limb movements may also be affected. With Myasthenia gravis there isn’t a cure but there are treatments that can control the symptoms and allow individuals to live a high quality of life and have a normal life expectancy.
Myasthenia gravis occurs when there is an error of the transmission of nerve impulses to muscles. It occurs when normal communication between nerve and muscle is interrupted at the neuromuscular junction the place where nerve cells connect with the muscles they control. Acetylcholine is normal when the electrical signals or impulses travel down a motor nerve, and the nerve ending release a neurotransmitter. With Myasthenia gravis the antibodies will block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction this prevents the muscle from contracting. However, antibodies to other proteins, such as Musk (Muscle-Specific Kinase) protein, can also lead to impaired transmission at the neuromuscular junction. Therefore, it is possible to test positive for either ACHR or Musk with Myasthenia gravis. About 15 percent of individuals with MG are seronegative for antibodies to the acetylcholine receptor, meaning the antibodies aren’t detectable in their blood (serum). It’s been discovered that a large fraction of these individuals have antibodies to muscle-specific kinase (MuSK). These antibodies are produced by the body within the immune system. Myasthenia gravis is considered an autoimmune disease because the immune system which is supposed to protect the body from foreign organisms mistakenly attacks itself.
Some individuals will have limited controlling eye movements and the eyelids this form of myasthenia gravis is referred to ocular MG. Generalized MG refers to people that have weakness involving muscles outside the eye region. In the most server form of generalized MG, many of the voluntary muscles of the body are involved, including those needed for breathing. The degree and distribution of muscle weakness for many people falls between those extremes.
Thymectomy for Myasthenia Gravis
The thymus gland plays a role with myasthenia gravis because it controls the immune function. It’s located in the chest behind the breast bone and is largest in children and will grow until puberty, and then gets smaller and is replaced by fat. During childhood the thymus helps the immune system by producing T-lymphocytes or T cells, a specific type of white blood cell that protects the body from viruses and infections. Within adults with myasthenia gravis the thymus will remain large and will have a cluster of immune cells in their thymus gland that is similar to lymphoid hyperplasia. Some individuals with myasthenia will develop thymomas (tumors of the thymus gland). Thymomas are most often harmless, but they can become cancerous. The thymus gland does play a role in myasthenia gravis, but the function isn’t understood. Scientist believe that the thymus gland may give incorrect instructions to developing immune cells, ultimately causing the immune system to attack its own cells and tissues and produce acetylcholine receptor antibodies setting the stage for the attack on neuromuscular transmission.
Is Myasthenia Gravis Hereditary?
No, Myasthenia Gravis is not inherited nor is it contagious. However, it can affect men and women with different racial and ethnic groups. Myasthenia gravis can impact young adult woman (under 40) and older men (over 60) but it can happen at any age and childhood. Occasionally, the disease may occur in more than one member of the same family. Myasthenia gravis is rarely seen in infants, the fetus may acquire antibodies from another affected with myasthenia gravis it’s called neonatal myasthenia. With neonatal myasthenia gravis its temporary and the child’s symptoms they can disappear within two to three months after birth.
Rarely, children of a healthy mother may develop congenital myasthenia. This not an autoimmune disorder as it is caused by defective genes that produce abnormal proteins in the neuromuscular junction. However, congenital myasthenia can cause similar symptoms to myasthenia gravis.
What is Myasthenia Crisis?
Myasthenia gravis is associated with a myasthenic crisis which is a medical emergency that can occur when the muscles that control breathing weaken so much that individuals require a ventilator to help them breathe. Around 15 to 20 percent of people with myasthenia gravis have an experience with one myasthenic crisis. The condition requires immediate medical attention and be triggered by infection, stress, surgery, or an adverse reaction to medication. However, up to one-half of people may have no obvious cause for their myasthenic crisis.
+ Double Vison
+ Facial expression Change
+ Impaired speech (dysarthria)
+ Walking (Gait) Difficulties
+ Difficulty Swallowing
+ Weakness in the arms, hands, fingers, legs, and neck
+ Numbness or Tingling
+ Shortness of Breath
Establishing a Myasthenia Gravis Diagnosis
+ Tacrolimus (Monthly)
Treatment for Myasthenia Gravis
Myasthenia gravis can be treated with several therapies to help reduce and improve muscle weakness. Thymectomy is an operation that removes the thymus gland (which is often abnormal in individuals with myasthenia gravis) and can reduce symptoms and may cure some people, possibly by rebalancing the immune system. Anticholinesterase medications which include mestinon or pyridostigmine that slow the breakdown of acetylcholine at the neuromuscular junction and will improve neuromuscular transmission and increase muscle strength. Immunosuppressive drugs will improve muscle strength that will suppress the production of abnormal antibodies. These medications include precision, azathioprine, mycophenolate mofetil, tacrolimus, and rituximab. These drugs can cause significant side effects and must be carefully monitored by a physician. Plasmapheresis and intravenous immunoglobulin these therapies may be options in severe cases of myasthenia gravis. Individuals can have antibodies in their plasma (a liquid component in blood) that attack the neuromuscular junction. These treatments remove the destructive antibodies, although their effectiveness usually only lasts for a few weeks to months.
Plasmapheresis is a procedure using a machine to remove harmful antibodies in plasma and replace them with good plasma or a plasma substitute.
Intravenous immunoglobulin is a highly concentrated injection of antibodies pooled from many healthy donors that temporarily changes the way the immune systems operates. It works by binding the antibodies that cause myasthenia gravis and removing them from circulation.
Some cases of myasthenia graves may go into remission either temporarily or permanently and muscle weakness may disappear completely so that medication can be discontinued. Stable, long-lasting complete remissions are the goal of the thymectomy and may occur in about 50 percent of individuals who undergo this procedure.
- Mestinon (pyridostigmine bromide)
- Intravenous Immune globulins (IVIg)
- Therapeutic Plasma exchange, or plasmapheresis
Get your Questions Answered about Myasthenia Gravis
ABOUT | My name is Jasmine Jones and I have generalized myasthenia gravis with thymoma I was diagnosed July 2018. My initial symptoms started with double vision and blurry vision and progressed very quickly to my entire body. Over the last year I’ve had my tumor removed in December of 2018 and numerous visits to doctors and blood work done. I’m still hopeful for remission and still moving forward.
AUTOIMMUNE DISEASES | Myasthenia Gravis