Myopathy refers to any disease that affects muscle tissue. Diseases of the muscle result in weakness, inflammation, tetany (spasms), or paralysis. Myopathy can be the result of either inherited or acquired causes.
Acute “acquired” myopathies, such as acute stiffness, spasm, or cramp, are common. Others are linked to exposure to an infectious agent, such as viruses or bacteria, or are inherited. However, certain cases of myopathy have no known associated risk factors.
Myopathy develops as the result of either inherited (congenital or genetic) disorders or acquired conditions of the muscles. Most commonly, people develop acquired myopathy from muscle fatigue, electrolyte imbalance, or dehydration, resulting in stiffness or cramping. Other causes of myopathy include immune disorders that cause inflammation and pain. Numerous inherited myopathies exist and may be associated with progressive weakness, atrophy (wasting), inflammation, muscle fiber metabolism dysfunction, muscle spasm, or rigidity.
The signs and symptoms of myopathy will vary depending on the type of disorder and its cause. The disease course for myopathy will also vary among individuals. Myopathy from acute causes, such as dehydration, resolves quickly, whereas those resulting from inherited causes typically last indefinitely. Myopathy symptoms may be mild such as a temporary cramp or very serious, including wasting and paralysis. Treatment options for myopathy include splinting, bracing, medications, physical therapy, and surgery.
In rare cases, myopathy may be a sign of a serious neuromuscular disorder. Seek immediate medical care (call 911) for serious symptoms, including difficulty lifting the front part of your foot and toes, weakness in your legs, feet or ankles, hand weakness or clumsiness, slurring of speech or trouble swallowing, or muscle cramps and twitching in your arms, shoulders and tongue.
Seek prompt medical care if you are being treated for myopathy but mild symptoms recur or are persistent.