Treatment of dermatomyositis is directed against inflammatory reactions, autoimmune disease, muscle weakness as described below.
These following points are guidelines to treatment.
1. Prednisone (a corticosteroid) is usually used as the drug of choice with high doses of 40 to 60 mg per day in adults or even higher. Repeat measurements of the muscle enzyme creatinine kinase, also called the CK titer, are usually used to monitor the success of this therapy and when stable low levels are reached after 10 to 12 weeks, the prednisone dosage is slowly reduced to the maintenance dose of about 10 to 15mg per day.
2. It is often not possible to stop the prednisone in adults in contrast to children, where it can often be stopped after 1 or 2 years of remission.
3. One major side-effect of chronic corticosteroid therapy is a myopathy. This is characterized by generalized muscle weakness. In these cases the corticosteroid must be discontinued and alternative therapy given.
4. Immunosuppressive therapy has been successful in controlling the autoimmune disease dermatomyositis by interfering with the autoantibody synthesis and cytotoxic lymphocyte (CD8 cells) production. Methotrexate, chlorambucil, cyclosporine and azathioprine have all been used for that purpose (Ref. 1,3 and 4).
5. Myositis that is caused by paraneoplastic substances from a hidden cancer, which causes cross reacting autoimmune antibodies with muscle cells, is much more difficult to treat. If at all possible, identification of the hidden cancer should be undertaken, and it should be attempted to remove the tumor. If this is not possible, then treatment by a cancer expert will likely contain the tumor with cyclosporine or a similar drug. This can often stabilize the condition.
6. The latest therapy is high dose intravenous immunoglobulin therapy (Ref. 5). Here several mechanisms seem to be utilized to interfere with the autoimmune response that causes dermatomyositis. Those cases that have more muscle related symptoms are doing particularly well on this therapy. The only problem is that this therapy is expensive. The other problem is that Gamimune, Gammagard and Sandoglobulinit, as some of the brand names are called, have to be given intravenously on a monthly basis.
References:
1.The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 50.
2. WA Schmidt et al. Clin Rheumatol 2000;19(5):371-377.
3. A Sauty et al. Eur Respir J 1997 Dec;10(12):2907-2912.
4. R Queiro-Silva et al. J Rheumatol 2001 Jun;28(6):1401-1404.
5. J Wada et al. Clin Exp Immunol 2001 May;124(2):282-289.
6. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.
7. Rakel: Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier
8. Suzanne Somers: “Breakthrough” Eight Steps to Wellness– Life-altering Secrets from Today’s Cutting-edge Doctors”, Crown Publishers, 2008
