黑料网

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction that results from antibodies that block or destroy nicotinic acetylcholine receptors (AChR) at the junction between the nerve and muscle. This prevents nerve impulses from triggering muscle contractions. Most cases are due to immunoglobulin G1 (IgG1) and IgG3 antibodies that attack AChR in the postsynaptic membrane, causing complement- Prednisone and azathioprine, two examples of immunosuppressants, can also be used. In some cases, the removal of the thymus through surgery may alleviate symptoms. During acute flare-ups of the condition, high-dose intravenous immunoglobulin and plasmapheresis may be utilized. Mechanical ventilation may be required if the breathing muscles become significantly weaker. Acetylcholinesterase inhibitors can be used to reduce airway secretions after intubation [1]. 50 to 200 people per million are affected by MG. Every year, it is discovered in three to thirty million people. Due to increased awareness, diagnosis has increased. MG typically affects men over the age of 60 and women under the age of 40. It rarely occurs in children often in adults . The majority of those affected can live fairly normal lives and have a normal life expectancy with treatment. The word comes from the Greek words mys, "muscle," astheneia, "weakness," and gravis, "serious," respectively. Painless muscle weakness, not fatigue, is the first and most common symptom of MG [2]. The muscle weakness gets worse as time goes on and gets better when there is time to rest. MG typically begins with ocular (eye) weakness; The weakness and fatigue typically become worse toward the end of the day. it could then advance to a more serious summed up structure, described by shortcoming in the limits or in muscles that oversee essential life capabilities. The term "ocular myasthenia gravis" refers to a subtype of MG in which muscle weakness is confined to the eyes, i.e. extraocular muscles, m. levator palpebrae superioris, and m. orbicularis oculi. Typically, this subtype evolves into generalized MG, usually after a few years. Eyelid drooping (ptosis) and double vision (dipl Dysphagia is a condition in which swallowing is difficult due to muscle weakness. This typically indicates that after an attempt to swallow, some food may remain in the mouth, or that food and liquids may regurgitate into the nose rather than the throat (velopharyngeal insufficiency). Additionally, difficulty chewing may be caused by weakness in the muscles of mastication, which move the jaw. Hard, fibrous foods tend to make chewing more difficult for people with MG [3]. About one-sixth of people with MG experience difficulty swallowing, chewing, and speaking as their first symptom. Dysarthria and hypophonia are conditions in which the muscles involved in speaking are weak. Speech may be sluggish, slurred, or have a nasal quality. In some instances, a singing hobby or profession must be abandoned.

An autoimmune synaptopathy is MG. When the immune system malfunctions and produces antibodies that attack the body's tissues, the disorder occurs. Human leukocyte antigen haplotypes are linked to increased susceptibility to myasthenia gravis and other autoimmune disorders [4]. The antibodies in MG attack the nicotinic acetylcholine receptor or a related protein called Musk, a muscle-specific kinase. Other, less common antibodies are found against the LRP4, agrin, and titin proteins. Other immune disorders are more common in relatives of people with myasthenia gravis. The cells in the thymus gland are a part of the body's immune system. The thymus gland in people with myasthenia gravis is abnormally large. It may contain immune cell clusters that indicate lymphoid hyperplasia, and the thymus gland may give immune cells incorrect instructions.

A third of pregnant women who already have MG have been known to experience an exacerbation of their symptoms, typically in the first trimester of pregnancy [5,6]. Pregnant mothers typically experience better signs and symptoms in the second and third trimesters. A child with TNM typically responds very well to acetylcholinesterase inhibitors, and the condition typically resolves over a period of three weeks, as the antibodies diminish, and generally does not result in any complications. Very rarely, an infant can be born with arthrogryposis multiplex congenita, which is the result of profound intrauterine weakness. Immunosuppressive therapy should be maintained throughout pregnancy because it reduces the chance of neonatal muscle weakness This is because maternal antibodies target the acetylcholine receptors in an infant. Sometimes, the mother doesn't show any symptoms at all.

Conclusion

The repetitive nerve stimulation test can help diagnose muscle fiber fatigue in people with MG. A thin needle electrode is inserted into various areas of a particular muscle to record the action potentials from several samplings of various individual muscle fibers in single-fiber electromyography, which is thought to be the most sensitive (though not the most specific) test for MG. The temporal variation in the firing patterns of two muscle fibers belonging to the same motor unit is measured. Diagnostic criteria include the proportion and frequency of particular abnormal action potential patterns, also known as "jitter" and "blocking." Jitter is the abnormal variation in the time it takes for adjacent muscle fibers in the same motor unit to produce an action potential. The failure of nerve impulses to elicit action potentials in adjacent muscle fibers of the same motor unit is referred to as blocking.

Conflict of interest

Author has no conflict of interest

1. Dalmau J, Rosenfeld MR (2008)

, ,

2. Shams'ili S, Grefkens J, de Leeuw B, van den Bent M, Hooijkaas H, et al. (2003)

, ,

3. Arawaka S, Daimon M, Sasaki H, Suzuki JI, Kato T (1998)

, ,

4. Graus F, Delattre JY, Antoine JC, Dalmau J, Giometto B, et al. (2004)

, ,

5. Graus F, Saiz A, Dalmau J. (2010). J Neurol 257: 509-517.

, ,

6. Pittock SJ, Kryzer TJ, Lennon VA (2004) . Ann Neurol 56: 715-719.

, ,