Myasthenia gravis (MG) is a disorder of neuromuscular transmission characterized by frailness and fatigability of skeletal muscles. The reason of myasthenia gravis is a breakdown in the normal communication between nerves and muscles. Myasthenia gravis is result by a defect in the transmission of nerve impulses to muscles. Normally, nerve endings discharge a substance that attaches to receptors on your 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 through the neuromuscular junction and binds to acetylcholine receptors which are activated and generate a muscle contraction. Myasthenia gravis often affects muscles in your head. Common symptoms are trouble with eye and eyelid movement, facial expression and swallowing. Symptoms vary in type and severity. Myasthenia gravis may cause double vision, drooping eyelids, difficulties with speech, chewing, and breathing, as well as weakness of your limbs.
Myasthenia gravis can affect people of any age, but it's more common in female younger than 40 or older than 70, and in men older than 50. Myasthenia gravis is not directly genetic nor is it contagious. There is no known cure for myasthenia gravis. Today, myasthenia gravis can be controlled. There are several therapies available to help reduce and improve muscle weakness. Medications used to treat the disorder include anticholinesterase agents such as neostigmine and pyridostigmine, which help improve neuromuscular transmission and increase muscle strength. Plasmapheresis, or plasma exchange, is used to modify the immune system malfunction.
It can be used to treat severe worsening of symptoms or in preparation for surgery (thymectomy). Other medicines can keep your body from making so lots of abnormal antibodies. Immunosuppressive medicines such as prednisone, cyclosporine, and azathioprine may also be used. These medications improve muscle strength by suppressing the production of abnormal antibodies. They must be used with careful medical follow-up because they may cause major side effects. Sometimes surgery to take out the thymus gland helps. Thymectomy is surgical removal of the thymus gland. It is usually performed on patients with a tumor of the thymus (thymoma).