Scientists have not yet discovered the precise cause of polymyositis. Many of the characteristics of polymyositis are similar to other autoimmune inflammatory diseases (in autoimmune diseases, the antibodies that normally fight against foreign substances, like bacteria or viruses, attack the tissues of the body instead).

Polymyositis is most common among adults aged 30-50, and women are more likely than men to develop polymyositis.

Polymyositis at a glance:

• Polymyositis is a systemic disorder that causes inflammation of the connective tissues in the body. Over time, polymyositis causes degeneration of the muscles in the shoulders, neck, arms and hips.
• The cause of polymyositis is unknown. Researchers believe it may be a type of autoimmune disorder in which the body attacks its own tissues.
• Symptoms include fatigue, difficulty speaking or swallowing, and muscle weakness that worsens over time.
• Treatment includes corticosteroids and other medications that suppress the immune system, as well as speech and physical therapy.

Symptoms of Polymyositis

Polymyositis affects the muscles of the shoulders, upper arms, upper back, neck, and hips, making them weak and tender. Polymyositis can also cause problems with the heart, lungs, and muscles that regulate breathing.

The symptoms of polymyositis develop over several weeks or months, gradually becoming more severe. Symptoms may also change over the course of weeks or months.

Typical symptoms include:

• Progressive muscle weakness that occurs on both sides of the body symmetrically (for example, in both shoulders)
• Fatigue
• Difficulty swallowing or speaking
• Shortness of breath

As the symptoms of polymyositis worsen, it may become difficult to raise your head when lying down or to stand up from a seated position.

Treatment for Polymyositis

With several years of treatment, it may be possible for the symptoms of polymyositis to be significantly reduced or eliminated. Treatment for polymyositis will focus on reducing the symptoms of the condition and improving muscle functionality. When treated early, treatment is usually very effective at reducing the symptoms of polymyositis.

Medication

Initial treatment will likely include immunosuppressant medication, such as corticosteroids like prednisone, to reduce the inflammation of the muscles. Other treatment options include different types of immunosuppressive therapies or medications and experimental biological therapies.

Therapeutic Treatments

Physical therapy exercises can help you maintain muscle strength, flexibility, and functionality. Speech therapy can also be useful for those who have difficulty swallowing or speaking. As the disease progresses, it may be necessary to consult with a registered dietician to learn how to modify your diet to make foods easier to chew and swallow.