Muscles waste away due to a lack of use or neurological problems, according to MedlinePlus. Disuse atrophy usually occurs because of a sedentary lifestyle or the inability to use the muscle due to a medical condition. Neurogenic atrophy is more serious and is caused by injury or disease.
Disuse atrophy occurs over time when an individual does not move the muscles enough. Office workers who spend most of the day at a desk may develop disuse atrophy. Casts that immobilize a bone for healing prevent muscle use, leading to muscle wasting. When astronauts go into space, they experience atrophy due to the lack of resistance from gravity, reports MedlinePlus.
Neurological conditions such as neuropathy, amyotrophic lateral sclerosis (ALS) and Guillain-Barré syndrome also result in muscle wasting. With these conditions, MedlinePlus indicates, the nerves that control the muscles become less effective at communicating and initiating movement.
As of 2015, ALS is fatal within 3 to 5 years of the initial symptoms. ALS causes the cells of the brain and spinal cord to die, leading to muscle wasting, according to WebMD. Muscle weakness in the hand, foot or tongue is often the first symptom.
Guillain-Barré treatment focuses on speeding recovery and avoiding complications. Treatment may involve the use of a breathing machine if the diaphragm becomes weak or a feeding tube if the condition involves the muscles that control swallowing, according to MedlinePlus.