Muscle weakness

Muscle weakness is a lack of muscle strength with many possible causes, broadly divided into true weakness and perceived weakness. True weakness is a primary symptom of skeletal muscle diseases such as muscular dystrophy and inflammatory myopathy, of neuromuscular junction disorders such as myasthenia gravis, and can also result from low potassium and other electrolyte disturbances. It may last from seconds to years depending on the underlying cause. The term is sometimes called myasthenia, from the Greek for muscle weakness. Because so many distinct disorders can produce it, muscle weakness functions in medical practice as a symptom and diagnostic starting point rather than a single disease, and its management depends entirely on identifying and treating the specific underlying cause.