The muscular system is composed of more than 600 muscles that serve varying functions in the human body. There are several diseases that can affect the muscular system. The broad categories of these conditions include infection, weakness, injury, genetic defects, cancers, inflammation and conditions that affect the muscle by interrupting or damaging the interface between muscles and the nerves that control them.
Injury
Muscle strains can occur by pulling or twisting a muscle during vigorous physical activity. People with strains experience pain, muscle spasms, decreased range of motion and sometimes paralysis of the muscle involved. If the strain caused a muscle tear the pain and disability from the injury can be significant. Treatments for strains include rest, ice to reduce the inflammation, compression with a bandage or elastic wrap and elevation of the affected extremity. Rehabilitation exercises also help decrease long-term complication of the injury.
Genetic Muscle Conditions
The best-known genetic disease affecting the muscles is muscular dystrophy. In muscular dystrophy, the muscle fibers are unusually fragile and can damage easily. When damaged they are not replaced by other muscle cells, but by other non-muscular tissue. This leads to progressive muscle weakness, lack of muscle coordination, and loss of mobility. There are several forms of muscle dystrophy, with varying degrees of weakness. Symptoms usually appear during infancy. Eventually, the weakness can impair eating and breathing, which can lead to other conditions. There is no cure for muscular dystrophy.
Inflammatory Conditions
Inflammation of the muscles is known as myositis. It can be caused by infection, particularly of viruses like influenza and by autoimmune conditions (conditions in which the body's immune system attacks healthy cells by mistake). Dermatomyositis is an autoimmune condition that results in chronic muscle inflammation, which eventually leads to muscle weakness. The other characteristic symptom of dermatomyositis is a rash with purplish discoloration that appears the eyes and over certain joints. Polymyositis is another autoimmune condition of chronic muscle inflammation. The weakness of polymyositis can affect movement but also make swallowing and breathing difficult. There is no cure for either condition but the symptoms can be treated with physical therapy, rest and potent anti-inflammatory medications like steroids.
