Muscle atrophy is usually caused by a lack of physical activity.
When illness or injury makes it difficult or impossible for you to move your arms or legs, lack of mobility can cause muscle atrophy. Over time, without regular movement, your arm or leg may start to look smaller, but no shorter than the one you're able to move.
In some cases, muscle wasting can be reversed with proper diet, exercise, or physical therapy.
Symptoms of muscle atrophy
- One of your arms or legs is noticeably smaller than the other.
- You have significant weakness on one side of your limb.
- You haven't exercised for a long time.
If you think you may have muscle wasting or are unable to move normally, call your doctor to schedule a complete physical exam. You may have an undiagnosed condition that needs treatment.
Causes of muscle atrophy
Muscle atrophy may also occur if you are bedridden or unable to move certain body parts due to a medical condition. For example, astronauts may experience muscle atrophy after being weightless for several days.
Other causes of muscle atrophy include:
- Prolonged lack of physical activity
- Alcohol-related myopathy, muscle pain and weakness caused by long-term excessive drinking
- Injury, such as a torn or broken rotator cuff
- Spinal cord or peripheral nerve injury
- Long-term corticosteroid therapy
Certain medical conditions may cause muscle wasting by causing muscle atrophy or making movement difficult. These include:
- Amyotrophic lateral sclerosis (ALS) , which affects nerve cells that control voluntary muscle movement
- Dermatomyositis , which causes muscle weakness and rash
- Guillain-Barre syndrome , an autoimmune disease that causes neuroinflammation and muscle weakness
- Multiple sclerosis , an autoimmune disease in which the body destroys the protective covering of nerves
- Muscular dystrophy , a genetic disorder that causes muscle weakness
- neuropathy , damage to a nerve or group of nerves resulting in loss of sensation or function
- Osteoarthritis , which causes reduced joint movement
- Polio , a viral disease that affects muscle tissue and can cause paralysis
- Polymyositis , an inflammatory disease
- Rheumatoid arthritis , a chronic inflammatory autoimmune disease affecting the joints
- Spinal muscular atrophy , a genetic disorder that causes muscle atrophy in the arms and legs
How is muscle atrophy diagnosed?
Your doctor will ask for a complete medical history. You may be asked to:
- Tell them about old or recent injuries and previously diagnosed medical conditions
- List prescription, over-the-counter, and supplements you are taking
- Describe your symptoms in detail
Your doctor may also order tests to help diagnose and rule out certain diseases. These tests may include:
- blood test
- Magnetic Resonance Imaging (MRI)
- Computed tomography (CT) scan
- nerve conduction studies
- Muscle or nerve biopsy
- Electromyography (EMG)
Based on the results of these tests, your doctor may refer you to a specialist.
How is muscle atrophy treated?
- physical therapy
- Ultrasound therapy
- dietary changes
Recommended exercises may include water exercises to help make movement easier.
A physical therapist can teach you the proper way to exercise. They can also move your arms and legs for you if you have trouble moving.
Ultrasound therapy is a non-invasive procedure that uses sound waves to aid healing.
If your tendons, ligaments, skin, or muscles are too tight to move, you may need surgery. This condition is called a contracture deformity.
If your muscle wasting is caused by malnutrition, surgery may be able to correct the contracture deformity. It can also correct your condition if a tendon tear is causing your muscles to atrophy.
If malnutrition is the cause of muscle wasting, your doctor may recommend dietary changes or nutritional supplements.