Editor’s Note: This post was verified and updated on 8/20/19. Thank you.
Myasthenia Gravis (MG) is one of the possible diseases I am being tested for by my new neurologist. I completely understand why he thinks it’s a good fit. Not only would MG explain a number of my symptoms, my understanding is that it also has the interesting if dubious honor of being caused by a mutation in the same chromosome as the one that causes Ehlers-Danlos Syndrome. After extensive research and the strong ancestral evidence behind me, I think I am a better candidate for the EDS diagnosis, but I’m going to go through all the testing to be sure. As promised, here is a look at the rare and debilitating neuro-muscular disease myasthenia gravis.
Myasthenia Gravis Symptoms
According to the National Institute of Neurological Disorders at the NIH, MG is a chronic autoimmune neuro-muscular disease characterized by varying degrees of weakness of the skeletal (voluntary) muscles of the body. The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity and improves after periods of 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, neck and limb movements may also be affected.
Although myasthenia gravis may affect any voluntary muscle, muscles that control eye and eyelid movement, facial expression, and swallowing are most frequently affected. The onset of the disorder may be sudden and symptoms often are not immediately recognized as myasthenia gravis.
In most cases, the first noticeable symptom is weakness of the eye muscles. In others, difficulty in swallowing and slurred speech may be the first signs. The degree of muscle weakness involved in myasthenia gravis varies greatly among individuals, ranging from a localized form limited to eye muscles (ocular myasthenia), to a severe or generalized form in which many muscles—sometimes including those that control breathing—are affected. Symptoms, which vary in type and severity, may include a drooping of one or both eyelids (ptosis), blurred or double vision (diplopia) due to weakness of the muscles that control eye movements, unstable or waddling gait, a change in facial expression, difficulty in swallowing, shortness of breath, impaired speech (dysarthria), and weakness in the arms, hands, fingers, legs, and neck.
The Mechanisms Behind MG
Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles. It occurs when normal communication between the nerve and muscle is interrupted at the neuromuscular junction—the place where nerve cells connect with the muscles they control. Normally when impulses travel down the nerve, the nerve endings release a neurotransmitter substance called acetylcholine. Acetylcholine travels from the neuromuscular junction and binds to acetylcholine receptors which are activated and generate a muscle contraction.
In myasthenia gravis, antibodies block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction, which prevents the muscle contraction from occurring. These antibodies are produced by the body’s own immune system. Myasthenia gravis is an autoimmune disease because the immune system—which normally protects the body from foreign organisms—mistakenly attacks itself.
EMG and muscle biopsy are often used for diagnosis along with blood tests to determine if the immune system is manufacturing the necessary antibodies. I am halfway there and so far it doesn’t appear to be a match, for all that my symptoms line up. It does however sound very much like a chronic illness population I would like to support here at the Zebra Pit, so if you have and like to write about the condition, drop me an email using our Contact form.
Update: It turns out I do not have MG, but I really enjoyed learning about this fascinating condition and considering the differences and similarities between my own symptoms and this disorder. I hope that you found this post useful and have learned more about this rare neuro-muscular condition.