atophied muscles in arms

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My 62 year old brother has had joint problems for many years.  He had double knee replacement and both his shoulders need re-positioned as his work has deteriated them.  He also is having disc problems with his back.  He was taking too many drugs to relieve the pain (cortizone related) and ended up in the hospital on an overdose.  When he was taken to his room, we noticed that from his shoulders down his arms it looked like his arms had shrunk.  He has very little use now of his arms.  He also ended up back in the hospital as he had infection in one of his shoulders around the joint.  What is going on with him and what should he be doing to help himself at this point?

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His condition of his muscles weakening in his arms was gradual with the deteriation of his joints.  Could this have been caused with the prednizone he was taking and the pain killers?  Then when he went to the hospital the first time the difference in his arms shrinking and his muscle problems in his arms was very noticeable.  It was like overnight his arms shrunk and he had trouble using his hands and arms to lift or reach.  Does this correlate to one of the muscle diseases you mentioned or is this a result of his pain killers and cortizone drug use?  And then having the infection in his shoulder which was probably there the 1st time he was in the hospital.

Thank you for your help

[Shazia Alam, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

Atrophy of the muscles, or wasting of the muscles, can be caused by a variety of conditions.  One possibility, given your brother’s history of painful joints is that he just isn’t using his muscles as much, causing a “disuse atrophy.”  Also, if he has cervical disc herniations, these may also cause atrophy, by disuse.  

Other causes are primary muscle diseases, such as problems affecting the nerves supplying those muscles, or the muscle tissue itself.  Some conditions include amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), primary lateral sclerosis. Examples of atrophying muscle diseases include muscular dystrophy, myotonia congenita, and myotonic dystrophy.

He may need to undergo an EMG (electromyelography), a test to assess the function of his nerves and muscle.  If it is just due to disuse, physical therapy and occupational therapy can help build up those muscles.  

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.