Myopathy is a disorder of the skeletal muscles. Muscle disorders arise from abnormalities that affect the muscle’s structure or metabolism, and have a variety of causes. Some are inherited while others are acquired. Inherited myopathies have a genetic basis and typically appear in childhood, but first symptoms can also appear in adulthood.  

Some examples of inherited muscle diseases include muscular dystrophies, congenital myopathies, metabolic myopathies, and myopathies related to channelopathies. Some examples of acquired muscle diseases include inflammatory myopathies and toxic myopathies

Myopathies can stem from systemic diseases including thyroid disorders, lupus, rheumatoid arthritis, Sjogren’s syndrome, sarcoidosis, amyloidosis, or another critical illness.

Symptoms of Myopathy

If you have a muscle disease, you may experience weakness, most likely in the thighs and upper arms. It can become difficult to climb stairs, rise from a chair, or lift your arms above your head. Cramping, stiffness, and soreness can also occur. Some myopathies can affect muscles in the hands or feet, or facial and eye muscles. In some cases, the problem can affect the heart and breathing muscles.

Causes of Myopathy

Inflammatory myopathies can occur when the body’s immune system causes inflammation in the muscle. This inflammation can stem from medications or environmental toxins. Infectious myopathies can be caused by viruses, bacteria, or parasites. Muscles can also be affected by systemic illnesses, including connective tissue diseases and endocrinopathies.

Treatments for Myopathy

If we suspect an acquired myopathy, such as inflammatory myopathy, we may recommend a muscle biopsy to evaluate the structure of the muscle. We typically treat inflammatory myopathy with oral immunosuppressant medications and occasionally chemotherapeutic agents. We recommend genetic testing and counseling if your condition is inherited.