Polymyositis is a disease that causes severe inflammation in skeletal muscle causing weakness and pain. Weakness is the predominant symptom. The proximal muscles of the legs are usually the most affected. Patients have difficulty walking up stairs and risng out of a chair. Proximal arm muscles are also affected. In severe cases heart muscle can be affected causing heart failure. The upper part of the pharynx and esophagus can be affected resulting in difficulty swallowing and choking. On occasion, there can also be inflammation in the lung. Inflamamtion in these areas if left untreated can cause scarring and tissue destruction. Therapy is largely prednisone but other agents have also been used with prednisone including methotrexate, azathioprine, cyclophosphamide, cellcept and TNF inhibitors. There has been an association of polymyositis and malignancy and careful cancer screening should be done.
About Alan Matsumoto, M.D.
Part-time Faculty, Division of Rheumatology
Johns Hopkins University