What is Myositis?

Myositis is a broad word for general inflammation of voluntary, or skeletal, muscles, which are used for bodily movement, and are consciously controlled. The causes of myositis are widely varied, and can range from the likeliest cause, autoimmune disorders, to other sources, such as infections and simple injuries. Another less common cause is the ingestion of the lipid-lowering drugs statins and fibrates, which can produce myositis symptoms.

The presence of myositis in the body can be indicated through elevated levels of creatine kinase, or CPK, in the blood. CPK is an enzyme that stimulates biochemical reactions. Normally, it adds phosphates to creatine, a naturally-occurring organic acid in the body that provides muscles with energy. When muscles are damaged, their cells break and release CPK into the bloodstream, causing these elevated levels.

There are four main, common causes of body myositis. One cause, idiopathic inflammatory myophathy, includes several subtypes. Each patient's myositis treatment will vary depending on the cause of inflammation.

Fibrodysplasia ossificans progressiva (FOP), a rare autoimmune disorder, involving malformation of the skeleton. It usually affects athletes who suffer from a blunt injury. Patients with FOP are encouraged to rest, and are given anti-inflammatory medication. Surgery is rarely required, but can be performed if the condition impedes movement.

Fibromyalgia is a chronic, but non-life threatening disease distinguished by pervasive skeletal muscle and soft tissue pain, as well sleep problems, migraines, fatigue and other symptoms. Normally, this affects a patient's back, shoulders, neck, hands and pelvic region. While the cause remains unknown, women are much more likely to develop the illness than men. Treatments can include antidepressant medications, non-steroidal anti-inflammatory drugs (NSAIDs), exercise, relaxation techniques and physical therapy.

Idiopathic inflammatory myopathies are diseases that affect connective tissue, causing muscle weakness, and constant inflammation. Dermatomyositis is an idiopathic inflammatory myopathy that also includes a skin rash. While it has no cure, it can be treated with physical therapy, medication, rest, orthotics, and heat therapy. The juvenile form of dermatomyositis, which affects children, involves many of the same treatments, but also relies heavily upon steroid medications, nutritional support and sunscreen use.

Another idiopathic inflammatory myopathy, polymyositis, is a rare and incurable disease that, in addition to muscle weakness and inflammation, can be characterized by an inability to swallow. It may be treated with medication and physical therapy; other possible treatments, including radiation therapy, remain under investigation. Sporadic inclusion body myositis (sIBM), an idiopathic inflammatory myopathy that is identified by a slow weakening and disentegration of muscles, typically affects elderly people, men more often than women. Also rare and incurable, its symptoms can be managed with medication and physical therapy; patients typically require a walking aid following the disease's progression.