What causes muscle disorders?
How do they develop? Do they come out of nowhere?
There are a variety of conditions that can affect the muscles, and people can be born with these disorders or can acquire them throughout life. Hereditary causes of muscle disorders include muscular dystrophy (such as the Duchenne or Becker type), which causes muscle weakness through mutations in proteins critical to muscle cell stability. Despite being born with these disorders, patients may not experience symptoms for several years, especially with the Becker type, which may not manifest until adolescence. There are also a number of autoimmune inflammatory conditions that affect the muscles, such as dermatomyositis and polymyositis. These conditions typically affect adults and can cause either large or small muscle weakness depending on the type. Another autoimmune condition that affects muscles is myasthenia gravis, in which the body produces antibodies against receptors on the muscle cells, which ultimately causes weakness. There are also medications which can cause adverse side effects on the muscles. Statins (popular medications used to help control cholesterol) have the potential to cause inflammation of the muscles which can cause pain and weakness. Steroids used for a variety of conditions can also cause weakness of the muscles. Similarly, conditions in the body that lead to an excess production of steroids (such as Cushing's Syndrome) can manifest as proximal (eg thigh or shoulder) muscle weakness. If you are concerned in any way about a type of muscle disorder that is affecting you, or if you are experiencing any symptoms that are concerning to you, then you should seek out the care of your primary care physician.
This answer is for general informational purposes only and is not a substitute for professional medical advice.
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