What are myopathies?
Myopathy is a general term for diseases that affect the muscles you use for voluntary movement, like those in your arms and legs. These conditions affect how your muscle fibers work, which makes it harder for muscles to contract and leads to muscle weakness. Some myopathies are inherited, meaning they are passed down through families, while others are acquired later in life.
Penn Medicine offers specialized neuromuscular disorder care for people with complex nerve and muscle conditions. Using advanced neurodiagnostic testing and close collaboration across specialties, our team works to identify the cause of muscle weakness and connect you with the most appropriate treatment options, including access to clinical trials when available.
Symptoms that may signal a muscle disorder
People with myopathies most often notice muscle weakness. Symptoms may develop gradually and can affect daily activities like climbing stairs, lifting objects, or getting up from a chair. Because different muscle diseases affect the body in different ways, symptoms can vary.
Other common symptoms include:
- Muscle pain or tenderness
- Fatigue with physical activity
- Trouble swallowing in some forms of myopathy
- Changes in skin appearance
Why myopathies develop
There are many causes of myopathy. Some forms develop when inflammation affects the muscles themselves, including conditions like polymyositis, dermatomyositis, and inclusion body myositis. Myopathies can also develop because of other medical conditions, including metabolic or endocrine disorders.
In some cases, medications can affect muscle tissue and lead to muscle weakness. This includes drugs used to treat high cholesterol and other conditions. Identifying the underlying cause is important because treatment often depends on what’s triggering the muscle damage.
Getting an accurate diagnosis
Diagnosing myopathies can be a challenge. Many different diseases affect the nerves and muscles, and they often cause similar symptoms.
Your provider will review your medical history and perform a physical exam. Testing may include biochemical tests, genetic testing, nerve biopsy, or muscle biopsy. Penn Medicine also uses advanced neurodiagnostic technology to analyze and monitor how the nervous system and muscles function. These tools help detect abnormalities that may not appear on standard imaging tests and can lead to faster, more accurate answers.
Managing myopathy disorders
Treatment depends on the specific type of myopathy and its underlying cause. In some cases, medications that affect the immune system may be adjusted to help control muscle inflammation. Physical therapy and guided exercise programs are often recommended to maintain strength, improve mobility, and support daily function.
At Penn Medicine, people with acquired myopathies like polymyositis, dermatomyositis, and inclusion body myositis are cared for at the Muscular Dystrophy Association (MDA) Clinic. The MDA supports a national network of specialized clinics focused on nerve and muscle disorders.