Polymyositis

=What is Polymyositis?= Polymyositis is a [|systemic] connective tissue disorder. It is characterized by degenerative or inflammatory changes in the muscles, which lead to some degree of [|muscular atrophy] and symmetric weakness. The areas that are most commonly affected are the hip, arms, pharynx, shoulders, and neck. It is one of several different types of [|myopathy] (see also myositis), and is a progressive condition which usually begins in adulthood. It can affect any age, however 60% of cases are found to occur within the age range of 30 and 60 years of age. Females are often affected more than males, and it occurs throughout the world. It can also be grouped with a skin rash, although then it would be called "[|dermatomyositis]." It also has the ability to affect other areas of the body, thus making it a systemic illness.

=What causes it?= The cause of polymyositis is currently unknown, although it can possibly be caused by an [|autoimmune reaction] or a viral infection of the skeletal muscle. An autoimmune reaction is where the body's immune system turns against the body and begins to attack and break down the muscle cells. This would result in the breakdown of muscle. The result of this assault would be muscular inflammation, along with muscle tenderness. Sometimes the onset of symptoms may be very acute, however the disease progresses relatively slowly. Failure to seek treatment one's ability to [|ambulate] may be compromised.

=What are the symptoms?= The symptoms are usually similar in all ages, although they seem to progress more rapidly in children. These symptoms would include: The muscle weakness may develop slowly, or appear quite suddenly. The voice may also be affected as a result of weakened throat muscles. A few other side things that may occur with polymyositis would be joint pain, inflammation of the heart, or lung disease. Each year, between 2 and 10 people per million develop this disease.
 * Symmetrical muscle weakness
 * Joint pain
 * Difficulty swallowing
 * Fever
 * Fatigue
 * Weight loss

=How is it diagnosed?= Diagnosing polymyositis can be a difficult and lengthy process, and is often suspected after a history and physical exam are at least completed. Then, blood will be obtained to check the creatinine phosphokinase level, which is usually elevated. An [|electromyogram] is then performed, which most often reveals muscle irritability. The next step would be the performance of a muscle biopsy. A muscle biopsy must be done to rule out other inflammatory myopathies or a disease trying to mimic polymyositis. As soon as the diagnosis is completed, treatment can be started.

=How is it treated?= It is most often treated with [|corticosteroid] medications. [|Prednisone] therapy is also used, and usually leads to improvement within only 2 to 3 months. At this point, the treatment can be tapered down so as to avoid the terrible side effects that come with overusing too much prednisone. Patients who are unresponsive to these forms of treatment often receive a supplementary or replacement [|immunosuppressant]. Patients who are unresponsive to the immunosuppressants may be started on intravenous [|immunoglobulin] treatments. Once again, when muscle strength is attained, treatment is slowly tapered off. Maintenance therapy with prednisone or immunosuppressants may or may not be continued.