Myasthenia Gravis

The Neuromuscular Division specializes in the diagnosis and 治疗 of disorders of the nerves and muscles.

定义

Myasthenia gravis (MG) is a disease that damages the communication between nerves and muscles. 这 can lead to muscle 弱点 that gets worse over time.

原因

MG happens when there is a problem with the immune system that causes it to attack a receptor that is needed for nerves to communicate with muscles. The reason why this happens 是未知的.

In some people, the thymus gland behind the breastbone may play a 角色. It makes antibodies that tell the body what to attack. The reason why this happens 是未知的.

The Thymus Gland

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风险因素

MG is most common in:

• Women who are less than 40 years of age
• Men over 60 years of age
• People with a family history of systemic lupus erythematosus

症状

症状 may grow worse over time. MG可能导致:

• Muscle 弱点 that increases with activity, and improves with rest
• Drooping eyelids
• Double and blurred vision
• Problems swallowing or speaking
• Trouble walking
• 手的弱点
• Trouble breathing

诊断

The doctor will ask about symptoms and past health. 一个物理 exam will be done. A doctor may be needed who specializes in the nervous system. 测试 可能包括:

• Blood tests—to look for antibodies
• Electromyography —to check the electrical activity of muscles
• Tensilon test—a medicine which will improve muscle strength in people with MG for a short time

Pictures of the thymus may be taken. 这 can be done with:

• CT扫描
• 核磁共振成像扫描

治疗

There is no cure. The goal of 治疗 is to decrease muscle 弱点. It is mainly done by slowing the immune system. A second goal is to avoid a myasthenic crisis. 这 is when muscles become too weak to let you breathe properly. 这 is a medical emergency that will need breathing support.

Some people may have a period of time where muscle 弱点 improves enough to stop 治疗. It may be short term or long lasting. 治疗 options are:

药物

Medicine can help to calm the immune system. Options include:

• Acetylcholinesterase inhibitors
• 糖皮质激素
• Immunosuppressive drugs
• IV immunoglobulin therapy

血浆置换

这 过程 以 abnormal antibodies out of the blood. It may need to be repeated in cycles.

手术

The thymus may be 删除. It may improve symptoms. In some people, this may be long lasting.

支持性护理

Some people may need:

• Mechanical ventilation—if breathing has become difficult
• Physical and occupational Therapy—to improve some muscle 弱点 and to learn new ways to do daily tasks

Avoiding Medicine That May Worsen 症状

Some medicine can worsen MG such as:

• β-受体阻滞药
• Certain antibiotics
• Certain medicine used to treat mental health problems

预防

There are no current guidelines to prevent MG.

参考文献

• Juel VC, Massey JM. Myasthenia gravis. Orphanet J Rare Dis. 2007 Nov 6;2:44.
• Myasthenia gravis. EBSCO DynaMed Plus website. 可用 at: http://www.dynamed.com/topics/dmp~AN~T113873/Myasthenia-gravis .
• Myasthenia gravis fact sheet. National Institute of Neurological Disorders and 中风 website. 可以在: http://www.研究所.国家卫生研究院.gov/disorders/肌无力%5Fgravis/detail%5F肌无力%5Fgravis.htm.
• What is 肌无力 gravis (MG)? Myasthenia Gravis Foundation of America website. 可以在: http://www.肌无力.org/WhatisMG.aspx.
• 11/9/2015 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T113873/Myasthenia-gravis : Kuo CF, Grainge MJ, Valdes AM, et al. Familial aggregation of systemic lupus erythematosus and coaggregation of autoimmune diseases in affected families. 美国医学会实习医师. 2015;175(9):1518-1526.