Myasthenia gravis is marked by extreme tiredness and weakness of the muscles in the body. It is caused by lapse of communication between the nerves and the muscles. It is a type of autoimmune disorder wherein the body’s own immune system will attack the muscles causing muscular weakness. This disorder can cause blurred vision, unstable gait and difficulty in swallowing in addition to weakness in various parts of the body.
It is a chronic disorder requiring prolonged treatment of immunosuppressant agents. Though the disease cannot be cured still the symptoms can be managed by effective medications. The symptoms will not be of same degree for all people and the intensity of weakness of the voluntary muscles varies considerably. Often, the symptoms of weakness will be peak for some period followed by remission.
Symptoms :
Muscular weakness is the major sign of myasthenia gravis but the symptoms range from mild to severe. There are remission periods where there will not be any symptoms. Certain types of muscle groups are largely affected in this disease. If the eye muscles are affected it can cause blurred vision, drooping of eyelids and double vision. For most of the people affected with myasthenia gravis blurred vision is common. Double vision can be either horizontal or vertical and the disease slowly progresses.
When the throat and face muscles are affected, it can alter the normal speech and cause difficulty in chewing/swallowing. Choking is common when the throat muscles get weakened. In some cases, it can change the normal facial expression of the concerned person. For some people, the neck muscles and the muscles of arms and legs are affected causing difficulty in walking and pain in moving their hands.
Causes :
The concept of body movement is based on the signals received and sent by neurotransmitters. Nervous system has good communication with the muscular system and they release certain chemicals that are required by the concerned muscle. These chemicals are known as neurotransmitters which fit into the receptor sites of the muscle. But in the people with myasthenia gravis, the body’s own immunity will destroy such receptor sites that can receive special chemical called acetylcholine. Since there is no receptor site in the muscle system to receive acetylcholine the muscles may not receive enough nerve signals causing weakness. Antibodies released by the immune system will arrest the function of protein by name tyrosine kinase which is important in the formation of nerve muscular junction. When this happens, it can lead to muscular weakness or myasthenia gravis.