Myasthenia gravis (MG) is a neuromuscular disorder that causes weakness in the skeletal muscles, which are the muscles your body uses for movement. It occurs when communication between nerve cells and muscles becomes impaired. This impairment prevents crucial muscle contractions from occurring, resulting in muscle weakness.
According to the Myasthenia Gravis Foundation of America MG is the most common primary disorder of neuromuscular transmission. It’s a relatively rare condition that affects between 14 and 20 out of every 100,000 people in the United States.
What Are the Symptoms of Myasthenia Gravis?
The main symptom of MG is weakness in the voluntary skeletal muscles, which are muscles under your control. The failure of muscles to contract normally occurs because they can’t respond to nerve impulses. Without proper transmission of the impulse, the communication between nerve and muscle is blocked and weakness results.
Weakness associated with MG typically gets worse with more activity and improves with rest. Symptoms of MG can include:
- trouble talking
- problems walking up stairs or lifting objects
- facial paralysis
- difficulty breathing due to muscle weakness
- difficulty swallowing or chewing
- hoarse voice
- drooping of eyelids
- double vision
Not everyone will have every symptom, and the degree of muscle weakness can change from day to day. The severity of the symptoms typically increases over time if left untreated.
What Causes Myasthenia Gravis?
MG is a neuromuscular disorder that’s usually caused by an autoimmune problem. Autoimmune disorders occur when your immune system mistakenly attacks healthy tissue. In this condition, antibodies, which are proteins that normally attack foreign, harmful substances in the body, attack the neuromuscular junction. Damage to the neuromuscular membrane reduces the effect of the neurotransmitter substance acetylcholine, which is a crucial substance for communication between nerve cells and muscles. This results in muscle weakness.
The exact cause of this autoimmune reaction is unclear to scientists. According to the Muscular Dystrophy Association, one theory is that certain viral or bacterial proteins may prompt the body to attack acetylcholine.
According to the National Institutes of Health, MG typically occurs in people over the age of 40. Women are more likely to be diagnosed as younger adults, whereas men are more likely to be diagnosed at 60 or older.
How is Myasthenia Gravis Diagnosed?
Your doctor will perform a complete physical exam, as well as take a detailed history of your symptoms. They’ll also do a neurological exam. This may consist of:
Repetitive nerve stimulation test
Blood testing for antibodies associated with mg
Imaging of the chest using CT scans or MRI
What Are the Treatment Options For Myasthenia Gravis?
The goal of treatment is to manage symptoms and control the activity of your immune system. Corticosteroids and other immunosuppressants (such as Soliris, Cellcept, Azathioprine, etc) can be used to improve the symptoms associated with myasthenia gravis. These medications help minimize the abnormal immune response that occurs in MG. Additionally, cholinesterase inhibitors, such as pyridostigmine (Mestinon), can be used to increase communication between nerves and muscles. The treatment is individualized based on the symptoms.
Dr. Kashouty is a leading expert on the treatment of myasthenia gravis. He believes in using all possible tools in managing symptoms. The goal is to find the right personalized treatment for each person with myasthenia gravis to improve the quality of life.