Monday, September 15, 2014
My friend was recently diagnosed with Myasthenia Gravis. After doing some research about the disease on the internet, I am still confused about it. What exactly is Myasthenia Gravis? How did she get it? What are symptoms of this disease? Is it treatable?
What is myasthenia gravis?
Acquired myasthenia gravis is an autoimmune disease, where our own immune system is attacking the connection between the nerve and the muscle, causing the muscle to not be able to receive the information signal from the nerve. The connection between the nerve and the muscle is a chemical called acetylcholine, and myasthenia causes an attack against that chemical's binding site (the acetylcholine receptor). Our nerve becomes less able to communicate with our muscle, and so we develop painless weakness.
What are the symptoms of the disease?
It usually presents as fatiguing weakness of proximal muscles (shoulders, thighs, hips), diplopia (double vision), ptosis (droopy eyelids), and can even present with dysphagia (swallowing problems), dysarthria (slurred speech), and dyspnea (breathing weakness). Eye movement abnormalities are the most common symptom of myasthenia gravis. Fatiguing weakness is a hallmark, meaning the weakness fluctuates during the day (better after rest and worse after exertion).
How did she get it?
Myasthenia is autoimmune, meaning our own immune system is working against us. We are not sure why some people develop autoimmune disease. It is not like an infection, but more like diseases like rheumatoid arthritis and lupus. Some people, including young women and the elderly, seem to be more susceptible to acquiring autoimmune disorders.
Is it treatable?
Yes, the disease is treatable. We mainly use medications to treat myasthenia. Treatment is divided between symptomatic treatment with drugs, like Pyridostigmine, and Immunosuppressant therapy (steroids like prednisone, azathioprine). Symptomatic therapy keeps the chemical, acetylcholine, around the nerve/muscle junction. Immunosuppressant therapy turns down the immune system so it stops attacking the weakened connection. There is one surgical treatment, as well, called thymectomy, but this is not the treatment for every patient with myasthenia. With appropriate care from a physician familiar with the disease, your friend should be able to possess a good quality of life.
Robert W Neel, IV, MD
Assistant Professor of Neurology
College of Medicine
University of Cincinnati