Main cause of muscle involvement is direct Injury or overuse, such as sprains or strains; cramps or tendinitis; genetic disorders, like muscular dystrophies; Inflammations, such as myositis; electrolyte imbalances like hypokalaemia, hypocalcaemia etc.; direct Infections and certain medicines like stations etc..
Clinical examination, blood investigations including CPK total & EMG-NCV study is used to confirm the diagnosis.
Treatment and prognosis vary depending upon the etiology.